* chore: perf tweaks for actions/styles/classes
- check if we really need to add/remove the class (calling `includes` first is cheaper than always setting/removing it)
- check if we really need to update a style (calling `getPropertyValue/setProperty` is expensive)
- check if we should call the action's update function (this is not only a perf tweak but also a correctness fix)
closes#12652
* changeset
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Co-authored-by: Rich Harris <rich.harris@vercel.com>
Simon H