Handle Double Quotes and Newline Chars in Gemma-4 Tool Call Arguments

[mamei16]

Fixes #7476

Checklist:

• I have read the Contributing guidelines.

[oobabooga]

This looks correct. I wonder if bare backslashes in values (Windows paths, regex patterns, etc.) could still break things, since the template doesn't escape them either. Would parts[idx] = json.dumps(parts[idx])[1:-1] on the odd parts work as an alternative?