[Lens] setFocusTrap after animation is ended and not with timeout

[mbondyra]

Summary

Fixes #100653

@flash1293 you were suspecting that the line with setTimeout causes the problem, but that was actually solution to it, just not fixing all the cases. For some reason EuiFocusTrap messes up the animation when the element has a position: absolute. I am not sure what styles it modifies, didn't look enough to find a low-level root cause (I did spend some time on it, but I failed to figure it out).

But I think we can ensure to avoid the animation problem with running the callback function not in timeout function, but on the callback onAnimationEnd.

EDIT: I just realized we have an advanced setting about not using animations at all, I'll see if we should solve it differently in this case. EDIT 2: Still works correctly even with animations off.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 0d5082a
• Storybooks Preview

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
lens	1.3MB	1.3MB	-71.0B

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@elasticmachine merge upstream

[flash1293]

Tested in Chrome and Firefox and it works fine, LGTM. Way better than the old solution 👍

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	7.x

This backport PR will be merged automatically after passing CI.