Ensure current record is None after removing record from the group

The removal can trigger __select_changed on the list view which may set the
first record of the selection as the current record which may be the deleted
record.
This prevents the display triggered by record_modified to set the current
record in the selection as it has been removed from the group.

Closes #13712
(grafted from ed532372fe23eff7fe3e7c94b145bd87c5cf741d)

--HG--
branch : 6.0

tryton/tryton/gui/window/view_form/screen/screen.py

@@ -773,6 +773,9 @@ class Screen(SignalEvent):
             self.current_record = None
             record.group.remove(record, remove=remove, signal=False,
                 force_remove=force_remove)
+        # set current_record to None to prevent __select_changed
+        # to set deleted record as current_record
+        self.current_record = None
         # send record-changed only once
         record.signal('record-changed')