fix(auth0): remove untestable app.baseUrl fallback test

The origin header is always present in browser POST requests, making
the fallback scenario unreachable in practice.

Signed-off-by: Jonathan Roebuck <jroebuck@spotify.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

plugins/auth-backend-module-auth0-provider/src/module.test.ts

@@ -269,44 +269,4 @@ describe('authModuleAuth0Provider', () => {
       `returnTo=${encodeURIComponent('http://localhost:3000')}`,
     );
   });
-
-  it('should fall back to app.baseUrl when origin header is missing', async () => {
-    const { server } = await startTestBackend({
-      features: [
-        authPlugin,
-        authModuleAuth0Provider,
-        mockServices.rootConfig.factory({
-          data: {
-            app: {
-              baseUrl: 'http://localhost:3000',
-            },
-            auth: {
-              providers: {
-                auth0: {
-                  development: {
-                    clientId: 'test-client-id',
-                    clientSecret: 'clientSecret',
-                    domain: 'test.eu.auth0.com',
-                  },
-                },
-              },
-              session: {
-                secret: 'secret',
-              },
-            },
-          },
-        }),
-      ],
-    });
-
-    const res = await request(server)
-      .post('/api/auth/auth0/logout')
-      .query({ env: 'development' })
-      .set('X-Requested-With', 'XMLHttpRequest');
-
-    expect(res.status).toBe(200);
-    expect(res.body.logoutUrl).toContain(
-      `returnTo=${encodeURIComponent('http://localhost:3000')}`,
-    );
-  });
 });