fix: android background backups (#21795)

* upload using dart client

* add connectivity api

* respect backup network setting

* comment as to why we need to wait for setForegroundAsync call

* log assets skipped due to network constraint

* dynamic spawning -> false

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>
Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/pigeon/connectivity_api.dart

@@ -0,0 +1,20 @@
+import 'package:pigeon/pigeon.dart';
+
+@ConfigurePigeon(
+  PigeonOptions(
+    dartOut: 'lib/platform/connectivity_api.g.dart',
+    swiftOut: 'ios/Runner/Connectivity/Connectivity.g.swift',
+    swiftOptions: SwiftOptions(includeErrorClass: false),
+    kotlinOut: 'android/app/src/main/kotlin/app/alextran/immich/connectivity/Connectivity.g.kt',
+    kotlinOptions: KotlinOptions(package: 'app.alextran.immich.connectivity'),
+    dartOptions: DartOptions(),
+    dartPackageName: 'immich_mobile',
+  ),
+)
+enum NetworkCapability { cellular, wifi, vpn, unmetered }
+
+@HostApi()
+abstract class ConnectivityApi {
+  @TaskQueue(type: TaskQueueType.serialBackgroundThread)
+  List<NetworkCapability> getCapabilities();
+}