Add fix to route parentRef internal logic

[bjee19]

Proposed changes

Internally generate ParentRefs for each listener in the Gateway if a route does not specify a sectionName.

Problem: When a route does not specify a sectionName, it attaches to all attachable listeners on a Gateway. This is a problem internally when we try to bind the route to the listeners where duplicated hostnames between listeners can create AcceptedHostname conflicts and multiple ports on the listeners can overwrite the refStatus.ListenerPort.

Solution: When a route does not specify a sectionName, generate a ParentRef for each listener in the Gateway.

Testing: Manually tested that the scenario reported in #3400 does not occur anymore.

Closes #3400

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

Fixed bug that occurred when a route's ParentRef does not include a sectionName and the Gateway's listeners have duplicate hostnames. This would cause conflicts when the route tries to attach to all the listeners and falsely trigger validation checks around overlapping routes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.74%. Comparing base (ae9c118) to head (c84872f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3418      +/-   ##
==========================================
- Coverage   86.82%   86.74%   -0.09%     
==========================================
  Files         127      127              
  Lines       15020    15068      +48     
  Branches       62       62              
==========================================
+ Hits        13041    13070      +29     
- Misses       1830     1846      +16     
- Partials      149      152       +3     

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[sjberman]

I'd also add a release note that describes this bug

[salonichf5]

🚀