Python console small improvements (#15794)
Closes #15792
Closes #15793
Summary of the issue:
1. When going back in the Python console history, modifying a line modifies the history. As a consequence, some previous commands cannot be found anymore in the console history.
2. The clear command control+L in the console does not provide any feedback
Description of user facing changes
1. When going back in the console history, editing a line will not change the item in the history anymore
2. Clearing the console output with control+L will now report a confirmation message.
Description of development approach
1. Remove the line of code that was updating an item in the history.
2. Added a UI message when clearing the output.
