NewPublisher: Changing task on publishing instance

[iLLiCiTiT]

Brief description

Change of task on publishing instance does not fix invalid instance and it is not possible to have instance without set task which may be needed in some cases of publishing.

Changes

• changed Submit label to Confirm
• instance does not need to have set task but can have empty task (stored as None)
• change of invalid task on existing instance is propagated to instance properly
  • invalid task doesn't mean invalid asset
• it is captured TaskNotSetError in both creator dialog and publisher
• publish plugin IntegrateNew does not require task in anatomy data
• change of checkbox states using keys (space, backspace, enter) will also trigger change state of group checkbox
• tasks in combobox are sorted
• plugin is added to report after checks if should stop/pause publishing

Testing notes:

Try change subset template in settings to be with/without task and create instances or change their context afterwards.

• Ideal test scenario:

1. create instance with subset template with task
2. change subset template in settings to not contain task
3. change task on the instance to empty task and press confirm

• The same thing in oposite way
  This has an issue that current hosts using new publisher probably does not support this test.

[ynbot]

Task linked: OP-2880 NP Fix changing task on publishing instance