Fix comments performance

[ruggi]

Fix #4707

Problem:

The editor performance degrades heavily when the comments section is open, worsening linearly with the number of threads.

Fix:

The root cause is the useSelf hook, used specifically in useMyThreadReadStatus, which causes constant re-renders. This is due to the fact that useSelf includes the presence data, while we just need the user ID.

So, this PR adds a new hook that only returns the user ID (from the editor state, we don't even need the LB hooks for this) and replaced it wherever useSelf was used inefficiently.

Also, I replaced useEditorState with the ref variant for the canvas deltas used when clicking the threads in the sidebar.

[github-actions]

Try me

[relativeci]

Job #9778: Bundle Size — 62.2MiB (~+0.01%).

7b4345b(current) vs df0030c master#9759(baseline)

Warning

Bundle contains 66 duplicate packages – View duplicate packages

Bundle metrics   3 changes 2 regressions

	Current Job #9778	Baseline Job #9759
Initial JS	45.4MiB(~+0.01%)	45.4MiB
Initial CSS	0B	0B
Cache Invalidation	19.86%	19.86%
Chunks	26	26
Assets	30	30
Modules	4362(+0.02%)	4361
Duplicate Modules	471(+0.21%)	470
Duplicate Code	30.75%	30.75%
Packages	462	462
Duplicate Packages	65	65

Bundle size by type   1 change 1 regression

	Current Job #9778	Baseline Job #9759
JS	62.18MiB (~+0.01%)	62.18MiB
HTML	11.54KiB	11.54KiB

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View job #9778 report View fix/comment-section-perf branch activity

[github-actions]

Performance test results: