fix: consider oidc session events for authN milestones (#8089)

# Which Problems Are Solved

After migrating the access token events in #7822, milestones based on
authentication, resp. theses events would not be reached.

# How the Problems Are Solved

Additionally use the `oidc_session.Added` event to check for
`milestone.AuthenticationSucceededOnInstance` and
`milestone.AuthenticationSucceededOnApplication`.

# Additional Changes

None.

# Additional Context

- relates to #7822 
- noticed internally

internal/api/grpc/admin/restrictions_integration_allow_public_org_registrations_test.go

@@ -22,7 +22,7 @@ import (
 func TestServer_Restrictions_DisallowPublicOrgRegistration(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
 	defer cancel()
-	domain, _, iamOwnerCtx := Tester.UseIsolatedInstance(t, ctx, SystemCTX)
+	domain, _, _, iamOwnerCtx := Tester.UseIsolatedInstance(t, ctx, SystemCTX)
 	regOrgUrl, err := url.Parse("http://" + domain + ":8080/ui/login/register/org")
 	require.NoError(t, err)
 	// The CSRF cookie must be sent with every request.

internal/api/grpc/admin/restrictions_integration_allowed_languages_test.go

@@ -33,7 +33,7 @@ func TestServer_Restrictions_AllowedLanguages(t *testing.T) {
 		unsupportedLanguage       = language.Afrikaans
 	)
 
-	domain, _, iamOwnerCtx := Tester.UseIsolatedInstance(t, ctx, SystemCTX)
+	domain, _, _, iamOwnerCtx := Tester.UseIsolatedInstance(t, ctx, SystemCTX)
 	t.Run("assumed defaults are correct", func(tt *testing.T) {
 		tt.Run("languages are not restricted by default", func(ttt *testing.T) {
 			restrictions, err := Tester.Client.Admin.GetRestrictions(iamOwnerCtx, &admin.GetRestrictionsRequest{})