Update workmanager and migrate to Flutter embedding v2

android/app/src/main/AndroidManifest.xml

@@ -17,11 +17,14 @@
          additional functionality it is fine to subclass or reimplement
          FlutterApplication and put your custom class here. -->
     <application
-        android:name=".Application"
         android:label="HA Client"
         android:icon="@mipmap/ic_launcher"
         android:usesCleartextTraffic="true">
 
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+
         <meta-data
             android:name="com.google.firebase.messaging.default_notification_channel_id"
             android:value="ha_notify" />
@@ -33,13 +36,12 @@
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
             android:hardwareAccelerated="true"
             android:windowSoftInputMode="adjustResize">
-            <!-- This keeps the window background of the activity showing
-                 until Flutter renders its first frame. It can be removed if
-                 there is no splash screen (such as the default splash screen
-                 defined in @style/LaunchTheme).
             <meta-data
-                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
-                android:value="true" />-->
+                android:name="io.flutter.embedding.android.SplashScreenDrawable"
+                android:resource="@drawable/launch_background" />
+            <meta-data
+                android:name="io.flutter.embedding.android.NormalTheme"
+                android:resource="@style/NormalTheme" />
             <intent-filter>
                 <action android:name="FLUTTER_NOTIFICATION_CLICK" />
                 <category android:name="android.intent.category.DEFAULT" />