Scala 2.13: Fix ReverseRouting exhaustive match compilation error

The Play Framework has had reverse routing problems with match exhaustiveness before: playframework/playframework#465

Unfortunately the fix in that PR doesn't fix the compilation erros because Scala 2.13 cannot understand that this generated code does have an exhaustive match: https://gist.github.com/ioannakok/3dcf08ebffa4ebd7deb23aa1cda3f35b

```
[error] /Users/ioanna_kokkini/Projects/frontend/identity/conf/routes:23:1: match may not be exhaustive.
[error] It would fail on the following input: (_, _)
[error] GET         /form/:formReference                    controllers.FormstackController.formstackForm(formReference: String, composer: Boolean = false)
[error] /Users/ioanna_kokkini/Projects/frontend/applications/conf/routes:51:1: match may not be exhaustive.
[error] It would fail on the following input: (_, _, _, _, _)
[error] GET        /embed/atom/:atomType/:id                                            controllers.AtomPageController.render(atomType: String, id: String, isJsEnabled: Boolean = true, hasVerticalScrollbar: Boolean = false, inApp: Boolean = false)
```

One fix is to make sure that the routes are pointing to specific methods so that reverse routing doesn't try to pattern match on the parameters. We've introduced wrapper methods with different names so that the choice is explicit.

We're removing the route /embed/atom/:atomType/inapp because it became obsolete in 2019: https://github.com/guardian/frontend/pull/21897/files#r941555632

We have verified that this endpoint is not called anymore: https://logs.gutools.co.uk/s/dotcom/goto/4f0cdb70-1801-11ed-b499-9b0038f50029

Co-authored-by: Roberto Tyley <roberto.tyley@guardian.co.uk>

applications/app/controllers/AtomPageController.scala

@@ -98,12 +98,15 @@ class AtomPageController(
         )
     }
 
+  def renderNoJs(atomType: String, id: String): Action[AnyContent] = render(atomType, id, false, false)
+
+  def renderNoJsVerticalScroll(atomType: String, id: String): Action[AnyContent] = render(atomType, id, false, true)
+
   def render(
       atomType: String,
       id: String,
       isJsEnabled: Boolean,
       hasVerticalScrollbar: Boolean,
-      inApp: Boolean,
   ): Action[AnyContent] =
     Action.async { implicit request =>
       lookup(s"atom/$atomType/$id") map {

applications/conf/routes

@@ -48,10 +48,9 @@ GET        /index/contributors
 GET        /index/contributors/*contributor                                     controllers.TagIndexController.contributor(contributor)
 
 GET        /embed/video/*path                                                   controllers.EmbedController.render(path)
-GET        /embed/atom/:atomType/:id                                            controllers.AtomPageController.render(atomType: String, id: String, isJsEnabled: Boolean = true, hasVerticalScrollbar: Boolean = false, inApp: Boolean = false)
-GET        /embed/atom/:atomType/:id/nojs                                       controllers.AtomPageController.render(atomType: String, id: String, isJsEnabled: Boolean = false, hasVerticalScrollbar: Boolean = false, inApp: Boolean = false)
-GET        /embed/atom/:atomType/:id/nojs/scroll-y                              controllers.AtomPageController.render(atomType: String, id: String, isJsEnabled: Boolean = false, hasVerticalScrollbar: Boolean = true, inApp: Boolean = false)
-GET        /embed/atom/:atomType/:id/inapp                                      controllers.AtomPageController.render(atomType: String, id: String, isJsEnabled: Boolean = true, hasVerticalScrollbar: Boolean = true, inApp: Boolean = true)
+GET        /embed/atom/:atomType/:id                                            controllers.AtomPageController.render(atomType: String, id: String, isJsEnabled: Boolean = true, hasVerticalScrollbar: Boolean = false)
+GET        /embed/atom/:atomType/:id/nojs                                       controllers.AtomPageController.renderNoJs(atomType: String, id: String)
+GET        /embed/atom/:atomType/:id/nojs/scroll-y                              controllers.AtomPageController.renderNoJsVerticalScroll(atomType: String, id: String)
 POST       /story-questions/answers/signup                                      controllers.AtomPageController.signup()
 OPTIONS    /story-questions/answers/signup                                      controllers.AtomPageController.options()
 

identity/app/controllers/FormstackController.scala

@@ -27,6 +27,9 @@ class FormstackController(
 
   val page = IdentityPage("/form", "Form")
 
+  def formstackFormEmbed(formReference: String): Action[AnyContent] =
+    formstackForm(formReference, true)
+
   def formstackForm(formReference: String, composer: Boolean): Action[AnyContent] =
     fullAuthAction.async { implicit request =>
       if (Switches.IdentityFormstackSwitch.isSwitchedOn) {

identity/conf/routes

@@ -21,7 +21,7 @@ GET         /user/:vanityUrl/:activityType          controllers.PublicProfileCon
 ########################################################################################################################
 GET         /form/complete                          controllers.FormstackController.complete
 GET         /form/:formReference                    controllers.FormstackController.formstackForm(formReference: String, composer: Boolean = false)
-GET         /form/embed/:formReference              controllers.FormstackController.formstackForm(formReference: String, composer: Boolean = true)
+GET         /form/embed/:formReference              controllers.FormstackController.formstackFormEmbed(formReference: String)
 
 ########################################################################################################################
 # Account deletion