Fixed updater

lib/functions/check_app_updates.dart

@@ -0,0 +1,51 @@
+import 'dart:io';
+import 'dart:math';
+
+import 'package:store_checker/store_checker.dart';
+
+import 'package:adguard_home_manager/functions/compare_versions.dart';
+import 'package:adguard_home_manager/models/github_release.dart';
+import 'package:adguard_home_manager/services/http_requests.dart';
+
+Future<GitHubRelease?> checkAppUpdates({
+  required String appVersion,
+  required void Function(GitHubRelease?) setUpdateAvailable,
+  required Source installationSource
+}) async {
+  final result = await checkAppUpdatesGitHub();
+
+  if (result['result'] == 'success') {
+    final update = gitHubUpdateExists(appVersion, result['body']);
+
+    if (update == true) {
+      final release = appVersion.contains('beta')
+        ? result['body'].firstWhere((release) => release.prerelease == true)
+        : result['body'].firstWhere((release) => release.prerelease == false);
+
+      setUpdateAvailable(release);
+        
+      if (Platform.isAndroid) {
+        if (
+          installationSource == Source.IS_INSTALLED_FROM_LOCAL_SOURCE ||
+          installationSource == Source.IS_INSTALLED_FROM_PLAY_PACKAGE_INSTALLER ||
+          installationSource == Source.UNKNOWN
+        ) {
+          return release;
+        }
+        else {
+          return null;
+        }
+      }
+      else if (Platform.isIOS) {
+        return null;
+      }
+      else {
+        return release;
+      }
+    }
+    else {
+      setUpdateAvailable(null);
+    }
+  }
+  return null;
+}