[EncoderCacheManager] Remove unnecessary copy (#32800)

Signed-off-by: Lukas Geiger <lukas.geiger94@gmail.com>

vllm/v1/core/encoder_cache_manager.py

@@ -237,7 +237,7 @@ class EncoderCacheManager:
 
         Typically called when a request is finished, cancelled, or aborted.
         """
-        input_ids = self.get_cached_input_ids(request).copy()
+        input_ids = self.get_cached_input_ids(request)
         for input_id in input_ids:
             self.free_encoder_input(request, input_id)