feat(mobile): use shared native client (#25942)

* use shared client in dart

fix android

* websocket integration

platform-side headers

update comment

consistent platform check

tweak websocket handling

support streaming

* redundant logging

* fix proguard

* formatting

* handle onProgress

* support videos on ios

* inline return

* improved ios impl

* cleanup

* sync stopForegroundBackup

* voidify

* future already completed

* stream request on android

* outdated ios ws code

* use `choosePrivateKeyAlias`

* return result

* formatting

* update tests

* redundant check

* handle custom headers

* move completer outside of state

* persist auth

* dispose old socket

* use group id for cookies

* redundant headers

* cache global ref

* handle network switching

* handle basic auth

* apply custom headers immediately

* video player update

* fix

* persist url

* potential logout fix

---------

Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/lib/providers/backup/asset_upload_progress.provider.dart

@@ -1,4 +1,5 @@
-import 'package:cancellation_token_http/http.dart';
+import 'dart:async';
+
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
 /// Tracks per-asset upload progress.
@@ -30,4 +31,4 @@ final assetUploadProgressProvider = NotifierProvider<AssetUploadProgressNotifier
   AssetUploadProgressNotifier.new,
 );
 
-final manualUploadCancelTokenProvider = StateProvider<CancellationToken?>((ref) => null);
+final manualUploadCancelTokenProvider = StateProvider<Completer<void>?>((ref) => null);