GEN-1578: SAML redirect leads to 404 page on UI (#17978)

* move routes to callback router

* move callback routes to global router

* added comments

* make saml and confidential callback route public

openmetadata-ui/src/main/resources/ui/src/components/AppRouter/AppRouter.tsx

@@ -26,6 +26,8 @@ import AppContainer from '../AppContainer/AppContainer';
 import Loader from '../common/Loader/Loader';
 import { UnAuthenticatedAppRouter } from './UnAuthenticatedAppRouter';
 
+import SamlCallback from '../../pages/SamlCallback';
+
 const AppRouter = () => {
   const location = useCustomLocation();
 
@@ -92,6 +94,14 @@ const AppRouter = () => {
       <Route exact component={SignUpPage} path={ROUTES.SIGNUP}>
         {!isEmpty(currentUser) && <Redirect to={ROUTES.HOME} />}
       </Route>
+
+      {/* When authenticating from an SSO provider page (e.g., SAML Apps), if the user is already logged in, 
+          the callbacks should be available. This ensures consistent behavior across different authentication scenarios. */}
+      <Route
+        component={SamlCallback}
+        path={[ROUTES.SAML_CALLBACK, ROUTES.AUTH_CALLBACK]}
+      />
+
       {isAuthenticated ? <AppContainer /> : <UnAuthenticatedAppRouter />}
     </Switch>
   );

openmetadata-ui/src/main/resources/ui/src/components/AppRouter/UnAuthenticatedAppRouter.tsx

@@ -18,7 +18,6 @@ import { AuthProvider } from '../../generated/configuration/authenticationConfig
 import { useApplicationStore } from '../../hooks/useApplicationStore';
 import useCustomLocation from '../../hooks/useCustomLocation/useCustomLocation';
 import PageNotFound from '../../pages/PageNotFound/PageNotFound';
-import SamlCallback from '../../pages/SamlCallback';
 import AccountActivationConfirmation from '../../pages/SignUp/account-activation-confirmation.component';
 import { isProtectedRoute } from '../../utils/AuthProvider.util';
 import Auth0Callback from '../Auth/AppCallbacks/Auth0Callback/Auth0Callback';
@@ -76,10 +75,7 @@ export const UnAuthenticatedAppRouter = () => {
       {callbackComponent && (
         <Route component={callbackComponent} path={ROUTES.CALLBACK} />
       )}
-      <Route
-        component={SamlCallback}
-        path={[ROUTES.SAML_CALLBACK, ROUTES.AUTH_CALLBACK]}
-      />
+
       {!isSigningUp && (
         <Route exact path={ROUTES.HOME}>
           <Redirect to={ROUTES.SIGNIN} />