feat(mobile): add cast support (#18341)

* initial cast framework complete and mocked cast dialog working

* wip casting

* casting works!

just need to add session key check and remote video controls

* cleanup of classes

* add session expiration checks

* cast dialog now shows connected device at top of list with a list header. Discovered devices are also cached for app session.

* cast video player finalized

* show fullsize assets on casting

* translation already happens on the text element

* remove prints

* fix lintings

* code review changes from @shenlong-tanwen

* fix connect method override

* fix alphabetization

* remove important

* filter chromecast audio devices

* fix some disconnect command ordering issues and unawaited futures

* remove prints

* only disconnect if we are connected

* don't try to reconnect if its the current device

* add cast button to top bar

* format sessions api

* more formatting issues fixed

* add snack bar to tell user that we cannot cast an asset that is not uploaded to server

* make casting icon change to primary color when casting is active

* only show casting snackbar if we are casting

* dont show cast button if asset is remote and we are not casting

* stop playing media if we seek to an asset that is not remote

* remove https check since it works with local http IP addresses

* remove unneeded imports

* fix recasting when socket closes

* fix info plist formatting

* only show cast button if there is an active websocket connection (ie the server is accessible)

* add device capability bitmask checks

* small comment about bitmask

mobile/lib/utils/image_url_builder.dart

@@ -73,6 +73,10 @@ String getThumbnailUrlForRemoteId(
   return '${Store.get(StoreKey.serverEndpoint)}/assets/$id/thumbnail?size=${type.value}';
 }
 
+String getPlaybackUrlForRemoteId(final String id) {
+  return '${Store.get(StoreKey.serverEndpoint)}/assets/$id/video/playback?';
+}
+
 String getFaceThumbnailUrl(final String personId) {
   return '${Store.get(StoreKey.serverEndpoint)}/people/$personId/thumbnail';
 }