fix: handle component binding mutation

[dummdidumm]

#10359 (comment)

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[changeset-bot]

🦋 Changeset detected

Latest commit: f0380fd

The changes in this PR will be included in the next version bump.

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[Rich-Harris]

Realised that this code also wouldn't work if you converted the <Widget> in the test case to runes mode, but I don't think there's much we can/should do about that