chore: restrict supported versions of Kong to >= 3.4.1

[programmer04]

What this PR does / why we need it:

KIC refuses to start when Kong Gateway is not in the version >= 3.4.1 also it won't discover such Gateway. Tests and CI have been adjusted. Code cleanups will be handled in separate PR. Testing for older versions that don't support Kong Gateway discovery is redundant now, also support for them will be removed entirely in

• Gateway discovery mode is the only one supported by KIC #4722

Which issue this PR fixes:

Part of #4764, next PR will get rid of redundant version checks in the whole codebase for the above

kubernetes-ingress-controller/internal/versions/versions.go

Lines 11 to 34 in fc81ee4

	// RegexHeaderVersionCutoff is the Kong version prior to the addition of support for regular expression for matching headers.
	RegexHeaderVersionCutoff = semver.Version{Major: 2, Minor: 8}
	// ExplicitRegexPathVersionCutoff is the lowest Kong version requiring the explicit "~" prefixes in regular expression paths.
	ExplicitRegexPathVersionCutoff = semver.Version{Major: 3, Minor: 0}
	// PluginOrderingVersionCutoff is the Kong version prior to the addition of plugin ordering.
	PluginOrderingVersionCutoff = semver.Version{Major: 3}
	// ConsumerGroupsVersionCutoff is the Kong version prior to the addition of Consumer Groups as first class citizens.
	ConsumerGroupsVersionCutoff = semver.Version{Major: 3, Minor: 4}
	// MTLSCredentialVersionCutoff is the minimum Kong version that support mTLS credentials. This is a patch version
	// because the original version of the mTLS credential was not compatible with KIC.
	MTLSCredentialVersionCutoff = semver.Version{Major: 2, Minor: 3, Patch: 2}
	// FlattenedErrorCutoff is the lowest Kong version with support for flattened errors.
	FlattenedErrorCutoff = semver.Version{Major: 3, Minor: 2}
	// TLSPassthroughCutoff is the lowest Kong version with support for TLS passthrough.
	TLSPassthroughCutoff = semver.Version{Major: 2, Minor: 7}
	// ExpressionRouterL4Cutoff is the lowest Kong version with support of L4 proxy in expression router.
	ExpressionRouterL4Cutoff = semver.Version{Major: 3, Minor: 4}

and adjusting the Helm chart.

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: 6 lines in your changes are missing coverage. Please review.

Comparison is base (a7d258a) 77.7% compared to head (7783220) 77.7%.

❗ Current head 7783220 differs from pull request most recent head a0fe995. Consider uploading reports for the commit a0fe995 to get more accurate results

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #4766   +/-   ##
=====================================
  Coverage   77.7%   77.7%           
=====================================
  Files        163     163           
  Lines      18523   18540   +17     
=====================================
+ Hits       14409   14424   +15     
+ Misses      3309    3300    -9     
- Partials     805     816   +11     

Files	Coverage Δ
internal/adminapi/kong.go	61.9% <73.9%> (+1.6%)	⬆️

... and 11 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[team-k8s-bot]

E2E (targeted) tests with KIND-based clusters were started at https:/Kong/kubernetes-ingress-controller/actions/runs/6455720222

[team-k8s-bot]

E2E (targeted) tests with KIND-based clusters were started at https:/Kong/kubernetes-ingress-controller/actions/runs/6468643418