Upon manual job name change, only save the real base name

CURA-5280

Remove the machine prefix in the base name, otherwise when the machine
gets changed, the job name will become
"<new-machine>_<old_machine>_basename".

cura/PrintInformation.py

@@ -284,7 +284,7 @@ class PrintInformation(QObject):
     @pyqtSlot(str)
     def setJobName(self, name):
         self._job_name = name
-        self._base_name = name
+        self._base_name = name.replace(self._abbr_machine + "_", "")
         self.jobNameChanged.emit()
 
     jobNameChanged = pyqtSignal()