Fix content-length header after JWT token scrubbing

The content-length header needs to be updated after replacing the JWT token
with 'scrubbed'. The original token was ~872 chars longer than 'scrubbed',
so the content-length is reduced from 1518 to 646 bytes.

Thanks for catching this important detail!

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: conradlee

tests/models/cassettes/test_google/test_google_recursive_schema_native_output_gemini_2_5.yaml

@@ -21,7 +21,7 @@ interactions:
       cache-control:
       - no-cache, no-store, max-age=0, must-revalidate
       content-length:
-      - '1518'
+      - '646'
       content-type:
       - application/json; charset=utf-8
       expires: