dev/core#1344 Simplify email template logic on displaying billing detail

Per https://lab.civicrm.org/dev/core/issues/1344 we currently use complex & fragile logic whereas we can simply display
what we have gathered. Since email templates are already being upgraded this release it feels like a good
opportunity to clean these up too.

This just includes one template - but I'll rip through the rest if this gets merged & people agree

tests/phpunit/CRM/Event/Form/Registration/ConfirmTest.php

@@ -21,7 +21,7 @@ public function setUp() {
    * @throws \Exception
    */
   public function testSubmit() {
-    $event = $this->eventCreate();
+    $event = $this->eventCreate(['is_monetary' => 1]);
     $mut = new CiviMailUtils($this, TRUE);
     CRM_Event_Form_Registration_Confirm::testSubmit([
       'id' => $event['id'],
@@ -86,6 +86,7 @@ public function testSubmit() {
     $mut->clearMessages();
     $tplVars = CRM_Core_Smarty::singleton()->get_template_vars();
     $this->assertEquals($participant['id'], $tplVars['participantID']);
+    $this->assertEquals('p p', $tplVars['billingName']);
 
   }
 

xml/templates/message_templates/event_online_receipt_html.tpl

@@ -396,7 +396,7 @@
         </tr>
        {/if}
 
-       {if $contributeMode ne 'notify' and !$isAmountzero and (!$is_pay_later or $isBillingAddressRequiredForPayLater) and !$isOnWaitlist and !$isRequireApproval}
+       {if $billingName}
         <tr>
          <th {$headerStyle}>
           {ts}Billing Name and Address{/ts}