* Update deprecated `isHostedVideo` method to always return `true` since all oEmbeds are now supported.
* Disable `scanImage` for non-image media widgets.
* Ensure embed URL field element is matched from current media frame instance due to bug where media frames are not destroyed upon closing.
* Update error message for invalid video URLs to ask user to check the URL for validity.
Props gk.loveweb, octalmage, westonruter.
See #42039, #40935.
Fixes#41052.
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