Added ApiException as a cause to mapHttpStatusError

[kkashkovskii]

Problem

When the request fails before sending a request / receiving an HTTP response, the exception cause is ignored, and the client returns an empty error message:

Caused by: io.pinecone.exceptions.PineconeUnmappedHttpException: null
    at io.pinecone.exceptions.HttpErrorMapper.mapHttpStatusError(HttpErrorMapper.java:21)
    at io.pinecone.clients.Pinecone.handleApiException(Pinecone.java:794)
    at io.pinecone.clients.Pinecone.describeIndex(Pinecone.java:441) 

Solution

Added the apiException as the cause HttpErrorMapper.mapHttpStatusError to make debugging easier.

Type of Change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update
• [ ] Infrastructure change (CI configs, etc)
• [ ] Non-code change (docs, etc)
• [ ] None of the above: (explain here)

Test Plan

not required