Fix debug log message caused by breaking the long string (#812)

Fixes the printing of the type

Authors:
  - David Gardner (https://github.com/dagardner-nv)

Approvers:
  - Michael Demoret (https://github.com/mdemoret-nv)

URL: #812

morpheus/stages/postprocess/filter_detections_stage.py

@@ -200,7 +200,7 @@ def _build_single(self, builder: mrc.Builder, input_stream: StreamPair) -> Strea
 
             logger.debug(
                 f"filter_source was set to Auto, infering a filter source of {self._filter_source} based on an input "
-                "message type of {message_type}")
+                f"message type of {message_type}")
 
         if self._build_cpp_node():
             node = _stages.FilterDetectionsStage(builder,