fix(parsing): handle whitespace only strings (#2007)

* fix: add a check to handle empty or newline-only strings before calling `from_json`

* style: adjust comment format for better readability

Co-authored-by: Robert Craigie <robert@craigie.dev>

---------

Co-authored-by: SenorSpes <138108569+senorNox@users.noreply.github.com>
Co-authored-by: Robert Craigie <robert@craigie.dev>

Author: 2 people

src/openai/lib/streaming/chat/_completions.py

@@ -438,6 +438,8 @@ def _accumulate_chunk(self, chunk: ChatCompletionChunk) -> ParsedChatCompletionS
                 choice_snapshot.message.content
                 and not choice_snapshot.message.refusal
                 and is_given(self._rich_response_format)
+                # partial parsing fails on white-space
+                and choice_snapshot.message.content.strip()
             ):
                 choice_snapshot.message.parsed = from_json(
                     bytes(choice_snapshot.message.content, "utf-8"),