Modifies the `setVolume` function for video elements to properly handle muting without resetting the volume.

When the volume is set to 0.0, the video is muted without changing the volume itself, preventing issues with unmuting in certain browsers (like Chrome with Tap Emulation).

This ensures the user can mute and unmute videos as expected without affecting the volume settings.

Fixes: https://github.com/flutter/flutter/issues/156444