fix(log): do not log errors when parentRef kind is not Gateway

[randmonkey]

What this PR does / why we need it:

Do not log errors when a parentRef item is not referencing a Gateway. It is possibly that the route is managed by some other controllers, like using service mesh.

Which issue this PR fixes:

fixes #6584
Special notes for your reviewer:

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.9%. Comparing base (61a1f60) to head (c8af668).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #6692     +/-   ##
=======================================
+ Coverage   77.7%   77.9%   +0.1%     
=======================================
  Files        203     203             
  Lines      23836   23832      -4     
=======================================
+ Hits       18534   18570     +36     
+ Misses      4351    4315     -36     
+ Partials     951     947      -4     

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[pmalek]

Given that this became a problem how about adding a UT for IsRouteAttachedToReconciledGateway()? This func is used across the code base in several place so IMHO it would be worth adding tests for it. WDYT?

[randmonkey]

Given that this became a problem how about adding a UT for IsRouteAttachedToReconciledGateway()? This func is used across the code base in several place so IMHO it would be worth adding tests for it. WDYT?

Added unit tests.