Fix Response Info Assignment for Non-Model Return Types (#564)

[mdelriolanse]

Problem

The API clients were failing when attempting to attach _response_info to response data that doesn't support attribute assignment. This could occur when:

1. The return_data is an empty string
2. The return_data is a type that doesn't support setattr (e.g., primitives, immutable types)

In the async and sync clients, string responses weren't being handled, causing potential failures when the API returns string data that should have response info attached.

Solution

Added defensive handling for edge cases when attaching _response_info:

pinecone/openapi_support/api_client.py and pinecone/openapi_support/asyncio_api_client.py

• Added json import for parsing string responses
• Added comprehensive string handling:
  • Empty strings are converted to a dict with _response_info
  • Non-empty strings are parsed as JSON; if successful and the result is a dict, _response_info is added
  • Parse failures fall back to returning a dict with just _response_info
• Wrapped setattr call in try/except to gracefully handle types that don't support dynamic attribute assignment

Impact

• Prevents runtime errors when API responses are empty strings or unsupported types
• Ensures _response_info is available when possible, gracefully degraded when not

Breaking Changes

No breaking changes to existing functionality