Add max_response_size to cap response body reads

[neilverma526-alt]

Adds max_response_size to requests.request and Session.request to cap response body reads.

• Introduces requests.exceptions.ContentTooLarge.
• Enforces limits based on bytes actually read (streaming raises during consumption via iter_content/.content).
• Ensures connection is closed/released when limit exceeded to avoid pool deadlocks.
• Keeps behavior unchanged when max_response_size is not provided.

Tests:

• ./test.sh base
• ./test.sh new