chore(runtime): add mock-doc export in client runtime package.json (#5860) (#5861)

Co-authored-by: Christian Bromann <git@bromann.dev>

Author: saschanowak

package.json

@@ -43,6 +43,10 @@
       "import": "./internal/app-data/index.js",
       "require": "./internal/app-data/index.cjs"
     },
+    "./mock-doc": {
+      "import": "./mock-doc/index.js",
+      "require": "./mock-doc/index.cjs"
+    },
     "./compiler": {
       "import": "./compiler/stencil.js"
     },