fix: don't clear date input on temporarily invalid value

[dummdidumm]

fixes #7897
No test because this is only visually observable

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[changeset-bot]

🦋 Changeset detected

Latest commit: cfe0932

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

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[leonklingele]

It looks like this wasn't backported to Svelte 4. Did this slip?

[briandonahue]

Also wondering if we can get a fix in v4...

[cckalen]

Do we know if this issue still persists in v4?

[leonklingele]

Yup, hasn’t been backported yet.