controller: add consistency check for gateway object namespaces #6089

Job	Run time
changes	6s
E2E Test (Envoy Gateway latest)	10m 19s
Data Plane MCP Test (ubuntu-latest)	6m 18s
Unit Test (macos-latest)	7m 36s
Data Plane MCP Test (macos-latest)	5m 0s
CRD CEL Validation Test (macos-latest)	4m 9s
Controller Test (macos-latest)	4m 48s
Controller Test (ubuntu-latest)	1m 30s
CRD CEL Validation Test (ubuntu-latest)	1m 12s
Unit Test (ubuntu-latest)	2m 24s
Data Plane Test (ubuntu-latest)	4m 52s
E2E Test (Envoy Gateway v1.8.1)	11m 1s
E2E Test for aigw CLI	2m 45s
E2E Test for Inference Extensions	4m 17s
E2E Test for Upgrades (k8s v1.33.4)	14m 35s
E2E Test for Namespaced Controller	3m 55s
E2E Test for Upgrades (k8s v1.34.3)	12m 56s
E2E Test for Upgrades (k8s v1.35.0)	13m 45s
E2E Test for Upgrades (k8s v1.32.8)	14m 16s
Data Plane Test (macos-latest)	4m 39s
ci-required	2s
Push Docker Images	-1s
Push Helm chart	-1s
	2h 10m 23s

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