[BUG] When Activity Is Deleted the Parameter and Attributes Objects Are Not

[WolfgangDaniel]

To Reproduce

Steps to reproduce the behavior:

1. Go to a robot and delete an activity
2. Click on Save to cloud
3. Go to the database and check all the parameter and atribute objects for this robot
4. See error - the objects were not deleted

Expected behavior

When an activity of a robot gets deleted, all the associated parameter and attributes objects should be deleted as well

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser: [e.g. chrome, safari]
• JS IDE: [e.g. VS Code, Atom]
• (Version: [e.g. 22])