Old code to remove: process_command_alter_task() (for December 2024)

[prioux]

Between the Portal and the Bourreau exists a control channel; the Portal can send messages to trigger methods on the Bourreau side. One of the possible message implemented historically was "alter_tasks", but everything that it does has just now been replaced by BackgroundActivity models. There is a piece of code to detect and report if "alter_tasks" is ever invoked in the future, as an internal system message to 'admin'.

If in the main CBRAIN service we do not get any such messages by, say, early December 2024, we know we can remove it (and all other methods that depend on it too).