How to enable autoplay of audio/video in webview?

### What is the problem or limitation you are having?

I tested that there is no similar method in toga to realize `webView.getSettings().setMediaPlaybackRequiresUserGesture(false);` . How to solve it? I do require autoplay because I uses .set_content. I tried some methods of html but all failed. I think toga should provide some interfaces to change WebView settings, especially autoplay.

### Describe the solution you'd like

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### Describe alternatives you've considered

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### Additional context

_No response_

The issue names Toga's WebView and its set_content entry point, along with the media-playback setting it needs to expose. Locate the WebView backend implementations and any existing tests for set_content, then compare how platform-specific settings are handled. Done means autoplay can be configured through a documented, tested WebView interface.

Written by the indexing model from the issue text.