chore(oidc): remove legacy storage methods (#10061)

# Which Problems Are Solved

Stabilize the optimized introspection code and cleanup unused code.

# How the Problems Are Solved

- `oidc_legacy_introspection` feature flag is removed and reserved.
- `OPStorage` which are no longer needed have their bodies removed.
- The method definitions need to remain in place so the interface
remains implemented.
  - A panic is thrown in case any such method is still called

# Additional Changes

- A number of `OPStorage` methods related to token creation were already
unused. These are also cleaned up.

# Additional Context

- Closes #10027 
- #7822

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/api/oidc/integration_test/token_exchange_test.go

@@ -52,13 +52,6 @@ func setTokenExchangeFeature(t *testing.T, instance *integration.Instance, value
 	time.Sleep(time.Second)
 }
 
-func resetFeatures(t *testing.T, instance *integration.Instance) {
-	iamCTX := instance.WithAuthorization(CTX, integration.UserTypeIAMOwner)
-	_, err := instance.Client.FeatureV2.ResetInstanceFeatures(iamCTX, &feature.ResetInstanceFeaturesRequest{})
-	require.NoError(t, err)
-	time.Sleep(time.Second)
-}
-
 func setImpersonationPolicy(t *testing.T, instance *integration.Instance, value bool) {
 	iamCTX := instance.WithAuthorization(CTX, integration.UserTypeIAMOwner)
 

internal/api/oidc/integration_test/userinfo_test.go

@@ -34,22 +34,11 @@ func TestServer_UserInfo(t *testing.T) {
 	})
 	tests := []struct {
 		name    string
-		legacy  bool
 		trigger bool
 		webKey  bool
 	}{
 		{
-			name:   "legacy enabled",
-			legacy: true,
-		},
-		{
-			name:    "legacy disabled, trigger disabled",
-			legacy:  false,
-			trigger: false,
-		},
-		{
-			name:    "legacy disabled, trigger enabled",
-			legacy:  false,
+			name:    "trigger enabled",
 			trigger: true,
 		},
 
@@ -59,7 +48,6 @@ func TestServer_UserInfo(t *testing.T) {
 		// - By calling userinfo with the access token as JWT, the Token Verifier with the public key cache is tested.
 		{
 			name:    "web keys",
-			legacy:  false,
 			trigger: false,
 			webKey:  true,
 		},
@@ -68,7 +56,6 @@ func TestServer_UserInfo(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			_, err := Instance.Client.FeatureV2.SetInstanceFeatures(iamOwnerCTX, &feature.SetInstanceFeaturesRequest{
-				OidcLegacyIntrospection:             &tt.legacy,
 				OidcTriggerIntrospectionProjections: &tt.trigger,
 				WebKey:                              &tt.webKey,
 			})