Fix Android API level 22 obsolete warnings and add Addressables conditional compilation

Author: juicycleff

engines/unity/plugin/Editor/FlutterBuildScript.cs

@@ -51,8 +51,13 @@ private static bool BuildAddressablesIfEnabled(BuildTarget target)
                 return true; // Not enabled, skip
             }
 
+#if ADDRESSABLES_INSTALLED
             Debug.Log("Streaming enabled - building Addressables first...");
             return FlutterAddressablesBuildScript.BuildAddressablesForPlatform(target);
+#else
+            Debug.LogWarning("Streaming is enabled but Addressables package is not installed. Skipping Addressables build.");
+            return true;
+#endif
         }
 
         private static string[] GetScenes()

engines/unity/plugin/Editor/FlutterExporter.cs

@@ -277,7 +277,7 @@ public static void ExportIOS(string path)
         private static void ConfigureAndroidSettings()
         {
             // Set Android settings for Flutter integration
-            PlayerSettings.Android.minSdkVersion = AndroidSdkVersions.AndroidApiLevel22;
+            PlayerSettings.Android.minSdkVersion = AndroidSdkVersions.AndroidApiLevel25;
             PlayerSettings.Android.targetSdkVersion = AndroidSdkVersions.AndroidApiLevel33;
 
             // Scripting backend

engines/unity/plugin/Editor/FlutterProjectValidator.cs

@@ -152,11 +152,11 @@ private void ValidateSceneSetup()
         private void ValidatePlatformSettings()
         {
             // Android settings
-            if (PlayerSettings.Android.minSdkVersion < AndroidSdkVersions.AndroidApiLevel22)
+            if (PlayerSettings.Android.minSdkVersion < AndroidSdkVersions.AndroidApiLevel25)
             {
-                AddResult("Android Settings", "minSdkVersion must be at least 21 for Flutter",
+                AddResult("Android Settings", "minSdkVersion must be at least 25 for Flutter",
                     ValidationType.Error, () => {
-                        PlayerSettings.Android.minSdkVersion = AndroidSdkVersions.AndroidApiLevel22;
+                        PlayerSettings.Android.minSdkVersion = AndroidSdkVersions.AndroidApiLevel25;
                     });
             }
             else