ref(rules): Raise exception on keyerror (#70880)

Follow up from
#70831 (comment) to
make this raise an exception rather than just log an error.

src/sentry/buffer/redis.py

@@ -73,8 +73,7 @@ def callback(self, buffer_hook_event: BufferHookEvent, data: RedisBuffer) -> boo
         try:
             callback = self._registry[buffer_hook_event]
         except KeyError:
-            logger.info("buffer_hook_event.missing", extra={"key_name": buffer_hook_event.value})
-            return False
+            logger.exception("buffer_hook_event.missing")
 
         return callback(data)