Restore video tag attributes on tech change

New attempt to fix this issue #1367 related to the webkit-playsinline attribute missing.
Yeah, that's true. There's some overlap because of the translation from empty string to boolean, so I prefer they stay consistent here. Also I'm wondering if we couldn't remove the knownBooleans and switch every empty string value to a boolean. That might take a little research so not something we need to deal with in this pull request.