feat(KongPlugin): generate K8s Events for missing grant

[programmer04]

What this PR does / why we need it:

The previous PR

• feat(KongPlugin): generate K8s Events for misconfiguration #6814

mentioned

There are still logs that should be events and statuses related to plugins like in this helper for cross-namespace access, but it can be handled in a separate PR or issue.

this PR adresses it, now there is no error log in such situation and respective K8s Event is generated

default     4m8s        Warning   KongConfigurationTranslationFailed   httproute/httproute-testing-2        no grant found to referenced "third:fourth" plugin in the requested remote KongPlugin bind

for httproute/httproute-testing-2 that has annotation konghq.com/plugins that contains non-existent third:fourth.

Which issue this PR fixes:

Together with a dedicated (leftover mentioned in PR #6814) issue #6842 this PR closes #6540

Special notes for your reviewer:

Besides adjustment of the returned error function, isRemotePluginReferenceAllowed is moved closer to it actual and single usage to make the code easier to follow.

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

Attention: Patch coverage is 81.33333% with 14 lines in your changes missing coverage. Please review.

Project coverage is 77.0%. Comparing base (425d3ef) to head (1f4d4e6).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/dataplane/kongstate/kongstate.go	83.8%	9 Missing and 2 partials ⚠️
internal/gatewayapi/contraints.go	40.0%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #6841     +/-   ##
=======================================
- Coverage   77.1%   77.0%   -0.2%     
=======================================
  Files        210     211      +1     
  Lines      25281   25295     +14     
=======================================
- Hits       19508   19489     -19     
- Misses      4762    4791     +29     
- Partials    1011    1015      +4     

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