The model returned an empty response with no text or thoughts

### What happened?

While using the latest versions of Gemini CLI including (v 0.55.1) frequently the chat will end/terminate with the message `The model returned an empty response with no text or thoughts. This may be a transient API issue; please try again.`

After the error occurs, the F12 diagnostics show the message
>(node: 6156) MetadataLookupWarning: received unexpected error = Requested failed with status code 403 code = UKNOWN (Use `node --trace-warnings ...` to show where the warning was created`)

### What did you expect to happen?

When errors occur from the backend, Gemini CLI is expected to handle these errors and retry appropriately so the chat session continues successfully and to completion.

### Client information

Client Information

Run `gemini` to enter the interactive CLI, then run the `/about` command.

```console
> /about
# paste output here
```

### Login information

_No response_

### Anything else we need to know?

_No response_

Start by reproducing the failure in the interactive Gemini CLI using the reported v0.55.1 context, then inspect the F12 diagnostics for the MetadataLookupWarning and 403 response. Trace the handling of the empty model response and backend error; done means transient errors are handled or retried so the chat reaches completion instead of terminating empty.

Written by the indexing model from the issue text.