[Feat]: perf review and update

[Westbrook]

trafficstars

Code of conduct

• [X] I agree to follow this project's code of conduct.

Impacted component(s)

Menu Item, Tab, etc.

Description of the requested feature

As per https://github.com/lit/lit/issues/2629 make sure that users aren't surprised by slotchange not occurring.

Compare perf on using a bunch of Mutation Observers with the keyed directive and update components appropriately.

Mockups or screenshots

No response

Implementation notes or ideas

No response