fix: never use html optimization for mustache tags in hydration mode

[dummdidumm]

not sure how to add a test for this yet, as it needs to compilations, one for ssr one for client hydration

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Name	Status	Preview	Comments	Updated (UTC)
svelte-dev-2	❌ Failed (Inspect)			Jun 16, 2023 4:16pm

[benmccann]

.svelte-kit/output/client/_app/immutable/nodes on version-4 is 179.1kB and on this branch is 179.0 kB. I didn't think it'd get smaller!

[dummdidumm]

That's honestly surprising, since this change makes less things be matched by the data-svelte-h optimization - but maybe in this specific case it's actually smaller in the end because it results in less code?
Either way, gonna merge this 👍