[Canvas] Fix group layering

[crob611]

Fixes #114073
Fixes #46782

Elements and groups are combined into a single array, and then each is given a z layer value based on the index in that array.

So all groups were "higher" than every single element. So any single element could be over every element in the group, but the group would be selected if you click on it.

This change gives groups a z layer value equal to the highest z layer value of its children.

This also works for a group that is made up of other groups. The parent group will get the z-layer of the child group which gets the z-layer of it's highest child.

Edit....
Turns out that wasn't what was causing the bug on the original issue. That was caused by an element rotated to 90 or -90deg also getting an incorrect z layer in aero elastic. I've pushed a commit to fix that issue as well.

[crob611]

@elasticmachine merge upstream

[crob611]

@elasticmachine merge upstream

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: e670a06
• 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
canvas	1.0MB	1.0MB	+233.0B

History

• 💚 Build #159107 succeeded 5c6ca52

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[poffdeluxe]

@elasticmachine merge upstream

[crob611]

@elasticmachine merge upstream

[poffdeluxe]

Unless I'm misunderstanding, it still seems like the issue is still happening

:

[crob611]

@elasticmachine merge upstream

[poffdeluxe]

Great work, Dr. Robertson

[poffdeluxe]

Will also fix #46782

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: e3fd2f5
• Storybooks Preview

Test Failures

• [job] [logs] Default CI Group #13 / search examples Search session example should start search, save session, restore session using "restore" button

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
canvas	1015.3KB	1015.5KB	+240.0B

History

• 💚 Build #7019 succeeded ebcd69a
• 💔 Build #3367 failed a8b3029

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[kibanamachine]

The following labels were identified as gaps in your version labels and will be added automatically:

• v8.1.0

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[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	8.0

This backport PR will be merged automatically after passing CI.