fix: avoid chromium issue with dispatching blur on element removal

[trueadm]

Glad we found this now! Addresses the issue found in #13684 (comment) which is unrelated to block effects but rather a bug in Chromium https://chromestatus.com/feature/5128696823545856. This doesn't happen in any other browser engine.

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Latest commit: 212a068

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[dummdidumm]

What is the consequence of a blur event setting state when there's no active reaction? Does it have any consequences other than not throwing that validation error?

[trueadm]

@dummdidumm There are three bugs that can come out of this by having the wrong active_reaction.

1. the blur event handler reads state, causing the reaction to get a dependency when it shouldn't, leading to odd behaviour as things are now dependencies when they shouldn't be
2. the blur event triggers a state change, however the current reaction doesn't allow that leading to a mutation error, or a possible infinite updates if it's already been read in 1)
3. the event handler creates an effect, or derived and now they're owned by the wrong thing