Add support for using auto-tag on orphaned data

Previously, auto-tag would seem to be enabled if selecting an image in the orphaned container, but then error when trying to use it.

auto-tag is now enabled if selecting an image in the orphaned container or the orphaned container itself.

Testing
-----------
- Ensure there is some orphaned data.
- Attempt to use auto-tag when selecting the orphaned container
- Attempt to use auto-tag when selecting an image in the orphaned container

Also, as the code changes may have affected existing functionality:
- Attempt to use auto-tag when selecting the dataset container
- Attempt to use auto-tag when selecting an image in the dataset container

Fixes #11