feat: allow non-numeric values to be tweened by snapping immediately to new value

[Rich-Harris]

Right now, non-numeric values cause interpolation in tweened or Tween to fail unless you provide a custom interpolator. It would probably be more useful if they just snapped to their new value instead — if you need some slightly different behaviour (e.g. flipping at the halfway mark) then you can continue to provide your own interpolator, but with this PR it's no longer required.

Supersedes #8678, closes #7543.

Demo — without this PR, it chokes on the color change (yes, this effect could obviously be done with just CSS but you get the idea)

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🦋 Changeset detected

Latest commit: 209dbf0

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

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svelte	Minor

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Playground

pnpm add https://pkg.pr.new/svelte@14941