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/ios/Runner/Background/BackgroundWorker.g.swift

@@ -114,6 +114,7 @@ class BackgroundWorkerFgHostApiSetup {
 /// Generated protocol from Pigeon that represents a handler of messages from Flutter.
 protocol BackgroundWorkerBgHostApi {
   func onInitialized() throws
+  func showNotification(title: String, content: String) throws
   func close() throws
 }
 
@@ -136,6 +137,22 @@ class BackgroundWorkerBgHostApiSetup {
     } else {
       onInitializedChannel.setMessageHandler(nil)
     }
+    let showNotificationChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.BackgroundWorkerBgHostApi.showNotification\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
+    if let api = api {
+      showNotificationChannel.setMessageHandler { message, reply in
+        let args = message as! [Any?]
+        let titleArg = args[0] as! String
+        let contentArg = args[1] as! String
+        do {
+          try api.showNotification(title: titleArg, content: contentArg)
+          reply(wrapResult(nil))
+        } catch {
+          reply(wrapError(error))
+        }
+      }
+    } else {
+      showNotificationChannel.setMessageHandler(nil)
+    }
     let closeChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.immich_mobile.BackgroundWorkerBgHostApi.close\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
     if let api = api {
       closeChannel.setMessageHandler { _, reply in

mobile/ios/Runner/Background/BackgroundWorker.swift

@@ -119,6 +119,10 @@ class BackgroundWorker: BackgroundWorkerBgHostApi {
     })
   }
   
+  func showNotification(title: String, content: String) throws {
+    // No-op on iOS for the time being
+  }
+  
   /**
    * Cancels the currently running background task, either due to timeout or external request.
    * Sends a cancel signal to the Flutter side and sets up a fallback timer to ensure