feat: propagate translation failures for KongPlugin and KongClusterPlugin

[czeslavo]

What this PR does / why we need it:

Instead of just logging an error in case of an invalid KongPlugin or KongClusterPlugin's configuration, bubble up the translation failure so that the Programmed condition is populated with False and reason Invalid and an event is emitted.

Also drops unnecessary validation of plugin.PluginName which is handled on the Kubernetes API level thanks to the CRD validation (KongPlugin, KongClusterPlugin).

Which issue this PR fixes:

Noticed when working on #3344.

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

Patch coverage: 75.0% and project coverage change: +0.1% 🎉

Comparison is base (c768c7d) 67.5% compared to head (fca3c20) 67.6%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #4428     +/-   ##
=======================================
+ Coverage   67.5%   67.6%   +0.1%     
=======================================
  Files        159     159             
  Lines      18772   18784     +12     
=======================================
+ Hits       12679   12711     +32     
+ Misses      5328    5310     -18     
+ Partials     765     763      -2     

Files Changed	Coverage Δ
internal/dataplane/kongstate/util.go	90.8% <61.5%> (+0.9%)	⬆️
internal/dataplane/kongstate/kongstate.go	72.3% <81.8%> (+0.8%)	⬆️
internal/dataplane/parser/parser.go	83.4% <100.0%> (+0.7%)	⬆️

... and 6 files with indirect coverage changes

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