Fix converging edges swapping positions when selected

[lmac-1]

Description

This PR fixes a bug where converging edges would swap positions when selected on the diagram.

The issue was caused by sortOrderForSvg reordering edges based on selection state, which affected Dagre's layout decisions. The fix preserves stable edge order regardless of selection.

Before:

After:

See the bug in action: https://www.loom.com/share/302055f6f3b748f1a4523ef7ccef67af

Closes #4328

Validation steps

1. Open workflow with multiple branching points
2. Make sure your diagram is on auto layout mode
3. Click edges from different parent nodes
4. Click edges that lead to converging paths
5. Expected: All paths maintain their positions

Additional notes for the reviewer

1. If you have bigger workflows - perhaps click around on the paths and make sure that everything behaves as expected
2. I suspected that this sorting algorithm was to ensure that the edges stayed on top in terms of z-index. I've verified both with and without the fix that the behaviour remains the same when there are edges that are on top of each other.

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• I have used another model
• I have not used AI

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• I have performed an AI review of my code (we recommend using /review
  with Claude Code)
• I have implemented and tested all related authorization policies.
  (e.g., :owner, :admin, :editor, :viewer)
• I have updated the changelog.
• I have ticked a box in "AI usage" in this PR

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.33%. Comparing base (549de66) to head (b398d4e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4348      +/-   ##
==========================================
+ Coverage   89.29%   89.33%   +0.04%     
==========================================
  Files         425      425              
  Lines       19994    19994              
==========================================
+ Hits        17854    17862       +8     
+ Misses       2140     2132       -8     

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[doc-han]

Works perfectly 🎉
Can we remove the comments with the PR number in them?

Also, I'm yet to understand why the sort function was initially made to work in that manner(pushing the selected edge to the bottom).

[doc-han]

Nice fix.
I'm trying to understand why this code existed in the first place. Seems to have zero value and I can't understand why it was like this.

[doc-han]

Can we remove the comments with PR numbers? Thanks.

[lmac-1]

@doc-han thanks for the review. I've fixed the comments referring to the PR. Can you check it again?

Also re the sorting function, I asked my good friend Claude and it seems to think that it "ensures disabled edges render behind enabled edges in the SVG." So I think it's best if we keep it in!