fix(4995): dynamically set autofocus

[skippednote]

fixes #4995

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Tests

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[Conduitry]

From what I can tell looking at the compiled code, this will unconditionally call .focus() on elements as they are mounted (whether or not the autofocus={foo} expression is truthy), and won't call it again later if foo changes.

The first seems incorrect. If we want to support autofocus={foo}, at the very least it should only focus upon mounting if foo is true at that moment. I don't really have an opinion about how it should be handled later on, though. Maybe if foo ever changes from falsy to truthy we should .focus() again? I'm not sure.