Fix system note comparison and standardize note setup

What does this MR do?

• Fix system note comparison. We were comparing against double the message because there were two .original-note-content and jQuery combines the two nodes, https://jsfiddle.net/574qfbvx/
• Standardize note setup to dry things up and make sure if a system note ever does need to update, we collapse it properly.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

• MR commit system notes were oddly displayed after polling update

Does this MR meet the acceptance criteria?

• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #32551 (closed)

assigned to @iamphill

added regression label

resolved all discussions

approved this merge request

enabled an automatic merge when the pipeline for f6743cc4 succeeds

added 1 commit

• 682cfbb4 - Fix system note comparison and standardize note setup

Compare with previous version

@iamphill MWPS again please 👯

changed the description

marked the checklist item All builds are passing as completed

assigned to @filipa

@filipa ready to merge.

Looks like @iamphill is at a conference today.

Thank you @MadLittleMods! 🎉

resolved all discussions

approved this merge request

merged

mentioned in commit c19d58de

Picked into 9-2-stable, will go into 9.2.0-rc7.

mentioned in commit 95979035