Replace `except:` and `except Exception:` with a more granular exception

See feedback from gemini in PR https://github.com/googleapis/gapic-generator-python/pull/2549:

https://github.com/googleapis/gapic-generator-python/pull/2549#discussion_r2747934082

```
The except: on the next line is a bare except, which is a bad practice as it catches all exceptions, including system-exiting ones like SystemExit and KeyboardInterrupt. This can make debugging difficult and hide underlying issues. It would be better to catch a more specific exception, like Exception.

While there's a TODO in the template to remove this try/except block, improving it in the meantime would be beneficial.

This change should be applied to the template file: gapic/templates/%namespace/%name_%version/%sub/services/%service/_shared_macros.j2.

Suggested change in the template:

except Exception:
```

We should remove all usages of `except:` and replace them with `except Exception:` or a more granular exception

Search results for `except:`

https://github.com/search?q=repo%3Agoogleapis%2Fgapic-generator-python%20except%3A&type=code

Search results for `except Exception:`
https://github.com/search?q=repo%3Agoogleapis%2Fgapic-generator-python+%22except+Exception%3A%22&type=code