strip whitespace from llm response (#70392)

sometimes the LLM responds with trailing/beginning whitespace. strip it
out.

Author: JoshFerge

src/sentry/feedback/usecases/spam_detection.py

@@ -12,7 +12,7 @@
 def is_spam(message):
     is_spam = False
     response = complete_prompt(usecase=LLMUseCase.SPAM_DETECTION, prompt=PROMPT, message=message)
-    if response and response.lower() in ("junk", "[junk]"):
+    if response and response.strip().lower() in ("junk", "[junk]"):
         is_spam = True
 
     logger.info(