Pass the correct lines to the edit diff discussion form

What does this MR do and why?

This is part 3 of a 3-part change. The uses the new action introduced in part 1 to get the correct line range to provide to the discussion edit form (when editing an existing comment).

Part	Purpose	MR
1	Add diffs store action implementation	!202439 (merged)
2	Pass comment lines range to the reply box	!202464 (merged)
3	Pass comment lines range to the comment edit interface	👈🏻 You are here

References

• For #557266 (closed)

Screenshots or screen recordings

Before	After
Screencast_from_2025-08-25_22-17-54	Screencast_from_2025-08-25_22-17-11

How to set up and validate locally

1. Have a multi-line comment
2. Click pencil icon to edit the comment
3. Click the "Insert suggestion" button

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.