AuthN: Use typed namespace id inside authn package (#86048)

* authn: Use typed namespace id inside package

pkg/api/org_test.go

@@ -266,7 +266,7 @@ func TestAPIEndpoint_GetOrg(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.desc, func(t *testing.T) {
 			expectedIdentity := &authn.Identity{
-				ID:    "user:1",
+				ID:    authn.MustParseNamespaceID("user:1"),
 				OrgID: 1,
 				Permissions: map[int64]map[string][]string{
 					0: accesscontrol.GroupScopesByAction(tt.permissions),