Edit branch rule status check

What does this MR do and why?

Edit status check in the branch rules page. As of this MR, delete buttons are not functioning and will be addressed in #439401 (closed).

Resolves: #439396 (closed)

⚠ Note: changes in this MR are behind the :edit_branch_rules feature flag.

Implementation breakdown:

Description	Issue/MR
Add status checks drawer placeholder component	!160804 (merged)
Add status check in drawer	!161380 (merged)
Edit status check in drawer	👈 This MR
Update doc	#480250 (closed)

MR acceptance checklist

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Screenshots or screen recordings

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Screen_Recording_2024-08-21_at_3.59.38_PM

⚠ currently, the BE mutation does not support updating status checks for all branches. this will be addressed in #478016 (closed)

How to set up and validate locally

1. Enable the edit-branch-rules feature flag
2. View details on an existing branch rule with existing status check
   • Navigate to Project > Repository > Settings > Branch rules > View details
3. Select edit button
4. Update one or both fields
5. A success toast should appears, drawer should close, table should be updated

Related to #439401 (closed)