v1.1.18 of flutter_inappwebview_forge_platform_interface

A common platform interface for the flutter_inappwebview_forge plugin. Changelog excerpt: - Keep `dart:io`localhost types behind `dart.library.io`conditional exports so Flutter web WASM (`dart2wasm`) compilation can import the platform interface ([#2811](https://github.com/pichillilorenzo/flutter_inappwebview/issues/2811)). - Introduce `InAppLocalhostHttpRequest`as a `HttpRequest`typedef on VM…