fix: handle rate_limit_count=0 to prevent IndexError (#7635)

* fix: handle rate_limit_count=0 to prevent IndexError

* Update astrbot/core/pipeline/rate_limit_check/stage.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

---------

Co-authored-by: Soulter <37870767+Soulter@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: 3 people

astrbot/core/pipeline/rate_limit_check/stage.py

@@ -63,6 +63,8 @@ async def process(
                 timestamps = self.event_timestamps[session_id]
                 self._remove_expired_timestamps(timestamps, now)
 
+                if self.rate_limit_count <= 0:
+                    break
                 if len(timestamps) < self.rate_limit_count:
                     timestamps.append(now)
                     break