[6.2.3][6.3.0]Failed to save replica or test connection for Google PubSub

Failed to save replica  for Google PubSub


<img width="1431" height="831" alt="Image" src="https://github.com/user-attachments/assets/18c933fe-e589-4de4-8e09-12364be21a02" />


<img width="1420" height="808" alt="Image" src="https://github.com/user-attachments/assets/64e6e197-cbd1-4731-8e6b-868a7711f37e" />

This is due to backend‑side changes.：https://github.com/emqx/emqx/pull/18314


