test: add document sync test on appflowy cloud (#4163)

* test: add document sync test on appflowy cloud

* chore: add runner

* test: Stream has already been listened to.

* fix: using singleton subscription

* fix: using singleton subscription

frontend/appflowy_flutter/integration_test/util/dir.dart

@@ -0,0 +1,30 @@
+import 'dart:io';
+import 'package:path/path.dart' as p;
+
+Future<void> deleteDirectoriesWithSameBaseNameAsPrefix(
+  String path,
+) async {
+  final dir = Directory(path);
+  final prefix = p.basename(dir.path);
+  final parentDir = dir.parent;
+
+  // Check if the directory exists
+  if (!await parentDir.exists()) {
+    // ignore: avoid_print
+    print('Directory does not exist');
+    return;
+  }
+
+  // List all entities in the directory
+  await for (final entity in parentDir.list()) {
+    // Check if the entity is a directory and starts with the specified prefix
+    if (entity is Directory && p.basename(entity.path).startsWith(prefix)) {
+      try {
+        await entity.delete(recursive: true);
+      } catch (e) {
+        // ignore: avoid_print
+        print('Failed to delete directory: ${entity.path}, Error: $e');
+      }
+    }
+  }
+}