Update js_interop.dart

packages/_flutterfire_internals/lib/src/js_interop.dart

@@ -1,2 +1,14 @@
+// Copyright 2024, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// ignore_for_file: require_trailing_commas
+// DO NOT MOVE THIS FILE
+//
+// Other firebase packages may import `package:firebase_core/src/internals.dart`.
+// Moving it would break the imports
+//
+// This file exports utilities shared between firebase packages, without making
+// them public.
+
 /// This is a stub file to work around odd dart web compiler builder issues.
 export 'dart:js_interop';