Complete OIDC test migration to OpenShift Tests Extension framework

- Migrate test/e2e-oidc to OTE framework with Ginkgo v2 integration
- Implement dual-mode pattern supporting both Go tests and Ginkgo
- Add complete OIDC authentication test workflow (not just preconditions)
- Fix suite configuration to prevent duplicate test execution
- Resolve all unused variables and code issues
- Use proper OTE tags: [OIDC][Serial][Disruptive] TestExternalOIDCWithKeycloak [Timeout:3h]

Changes:
* test/e2e-oidc/external_oidc.go: New Ginkgo test registration with complete OIDC test implementation
* test/e2e-oidc/external_oidc_test.go: Simplified Go test wrapper for backward compatibility
* cmd/cluster-authentication-operator-tests-ext/main.go: Add e2e-oidc import and fix serial suite qualifier

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>

Author: Rohit Patil

cmd/cluster-authentication-operator-tests-ext/main.go

@@ -15,6 +15,7 @@ import (
 	_ "github.com/openshift/cluster-authentication-operator/test/e2e"
 	_ "github.com/openshift/cluster-authentication-operator/test/e2e-encryption-kms"
 	_ "github.com/openshift/cluster-authentication-operator/test/e2e-encryption-perf"
+	_ "github.com/openshift/cluster-authentication-operator/test/e2e-oidc"
 
 	"k8s.io/klog/v2"
 )
@@ -75,11 +76,12 @@ func prepareOperatorTestsRegistry() (*oteextension.Registry, error) {
 	// The following suite runs tests that must execute serially (one at a time)
 	// because they modify cluster-wide resources like OAuth configuration.
 	// Tests tagged with [Serial] and any of [Operator], [OIDC], [Templates], [Tokens] are included in this suite.
+	// Excludes [Disruptive] tests which run in the disruptive suite instead.
 	extension.AddSuite(oteextension.Suite{
 		Name:        "openshift/cluster-authentication-operator/operator/serial",
 		Parallelism: 1,
 		Qualifiers: []string{
-			`name.contains("[Serial]") && (name.contains("[Operator]") || name.contains("[OIDC]") || name.contains("[Templates]") || name.contains("[Tokens]"))`,
+			`name.contains("[Serial]") && !name.contains("[Disruptive]") && (name.contains("[Operator]") || name.contains("[OIDC]") || name.contains("[Templates]") || name.contains("[Tokens]"))`,
 		},
 	})