## Summary
Fix https://github.com/elastic/kibana/issues/83612
This PR doesn't change any behavior, as we're already supporting (and
awaiting) promises returned from `stop` calls to plugin, it just changes
the type's signature to reflect that.
Also removed empty `stop` methods from existing plugins to make
typescript happy.
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Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>