fix: strip segment text to remove extra blank lines in segmented reply (#8304)

* fix: strip segment text to remove extra blank lines in segmented reply

Fixes #8300

* refactor: optimize seg.strip() per PR review suggestion

Author: Blueteemo

astrbot/core/pipeline/result_decorate/stage.py

@@ -245,7 +245,8 @@ async def process(
                             for seg in split_response:
                                 if self.content_cleanup_rule:
                                     seg = re.sub(self.content_cleanup_rule, "", seg)
-                                if seg.strip():
+                                seg = seg.strip()
+                                if seg:
                                     new_chain.append(Plain(seg))
                         else:
                             # 非 Plain 类型的消息段不分段