Added implementation for failure handling method for WkWe…

[aaRopi]

…bview.

Description of Change

Added implementation for failure handling method for WkWebViewRenderer.

• WkNavigationDelegate has 2 methods for failure handling as can be seen here.

• Only one of them was implemented as can be seen from the source of WkWebViewRenderer here.

Issues Resolved

• fixes [Bug] WebView.Navigated event not fired when no internet available on iOS. #12312
• fixes [Bug] WebView.Navigated event not fired when there is an issue on iOS. #12732

API Changes

None

Platforms Affected

• iOS

Behavioral/Visual Changes

On iOS, when loading a url in the WebView, if there is no internet connection available, the WebView should fire a Navigated event with WebNavigationResult.Failure.

Before/After Screenshots

Not applicable

Testing Procedure

Tested with iOS 14 simulator.

• Hook into WebView.Navigated event.
• Run app on iOS (simulator or device) without internet connection.
• Handler for WebView.Navigated should be called now.

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)