[processing] Use silent feedback by default in processing.run

Relying on the iface messagebar feedback as a fallback is not
safe for standalone scripts. If callers want to use a message
bar feedback they should specify this feedback object specifically
when calling processing.run

Author: nyalldawson

python/plugins/processing/core/Processing.py

@@ -116,7 +116,7 @@ def runAlgorithm(algOrName, parameters, onFinish=None, feedback=None, context=No
             alg = QgsApplication.processingRegistry().createAlgorithmById(algOrName)
 
         if feedback is None:
-            feedback = MessageBarProgress(alg.displayName() if alg else Processing.tr('Processing'))
+            feedback = QgsProcessingFeedback()
 
         if alg is None:
             # fix_print_with_import