fix: update mock Supabase client to return session data

- Modified the `refreshSession` method in the mock Supabase client to return a session object along with the user, improving the accuracy of the mock implementation for testing purposes.

autogpt_platform/frontend/src/tests/integrations/mock-supabase-request.tsx

@@ -12,7 +12,7 @@ const mockSupabaseClient = {
     }),
     signOut: vi.fn().mockResolvedValue({ error: null }),
     refreshSession: vi.fn().mockResolvedValue({
-      data: { user: null },
+      data: { session: null, user: null },
       error: null,
     }),
   },