Error should be thrown to warn about the combination of response schema and google grounding / search tool

In the Python SDK, an error is thrown:
https://github.com/googleapis/python-genai/issues/665

In the Golang SDK, no error is thrown. The SDK just returns a response that looks like this as text:

```
<ctrl42>call:google_search.search{queries:
  [
    ]
}<ctrl43><ctrl44>
```

This should probably be documented somewhere or an error should be thrown in the SDK.

