I am running on web and getting this error. Error: MissingPluginException(No implementation found for method close on channel flutter_webview_plugin)

## System info

Issue occurs on: WEB
Plugin version: latest
Flutter doctor output:

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.0.0, on macOS 11.2.2 20D80 darwin-x64, locale en-PK)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[✓] Xcode - develop for iOS and macOS
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.1)
[✓] Connected device (1 available)

• No issues found!

## Steps to Reproduce
Simply just run it on web and the page doesn't load and through an exception.

## Logs

[+4371 ms] Error: MissingPluginException(No implementation found for method close on channel flutter_webview_plugin)
at Object.throw_ [as throw] (http://localhost:53868/dart_sdk.js:5334:11)
at MethodChannel._invokeMethod (http://localhost:53868/packages/flutter/src/services/system_channels.dart.lib.js:954:21)
at _invokeMethod.next ()
at http://localhost:53868/dart_sdk.js:39032:33
at _RootZone.runUnary (http://localhost:53868/dart_sdk.js:38889:58)
at _FutureListener.thenAwait.handleValue (http://localhost:53868/dart_sdk.js:33875:29)
at handleValueCallback (http://localhost:53868/dart_sdk.js:34435:49)
at Function._propagateToListeners (http://localhost:53868/dart_sdk.js:34473:17)
at _Future.new.[_completeWithValue] (http://localhost:53868/dart_sdk.js:34315:23)
at async._AsyncCallbackEntry.new.callback (http://localhost:53868/dart_sdk.js:34338:35)
at Object._microtaskLoop (http://localhost:53868/dart_sdk.js:39176:13)
at _startMicrotaskLoop (http://localhost:53868/dart_sdk.js:39182:13)
at http://localhost:53868/dart_sdk.js:34689:9
[ +6 ms] Error: MissingPluginException(No implementation found for method launch on channel flutter_webview_plugin)
at Object.throw_ [as throw] (http://localhost:53868/dart_sdk.js:5334:11)
at MethodChannel._invokeMethod (http://localhost:53868/packages/flutter/src/services/system_channels.dart.lib.js:954:21)
at _invokeMethod.next ()
at http://localhost:53868/dart_sdk.js:39032:33
at _RootZone.runUnary (http://localhost:53868/dart_sdk.js:38889:58)
at _FutureListener.thenAwait.handleValue (http://localhost:53868/dart_sdk.js:33875:29)
at handleValueCallback (http://localhost:53868/dart_sdk.js:34435:49)
at Function._propagateToListeners (http://localhost:53868/dart_sdk.js:34473:17)
at _Future.new.[_completeWithValue] (http://localhost:53868/dart_sdk.js:34315:23)
at async._AsyncCallbackEntry.new.callback (http://localhost:53868/dart_sdk.js:34338:35)
at Object._microtaskLoop (http://localhost:53868/dart_sdk.js:39176:13)
at _startMicrotaskLoop (http://localhost:53868/dart_sdk.js:39182:13)
at http://localhost:53868/dart_sdk.js:34689:9

Commencez par reproduire l’échec avec Flutter 2.0.0 sur le web et examinez comment le plugin gère les méthodes close et launch sur cette plateforme. C’est terminé lorsque la page web signalée se charge sans erreurs MissingPluginException, que le comportement requis de la plateforme est défini et couvert par un test approprié.

Rédigé par le modèle d'indexation à partir du texte de l'issue.