Error message from adding a video without a camera

[annkennedy]

Another one from re-populating the database: if I add a video with no camera, I get an error message in terminal

  File "K:\Github\bento\src\db\schema_sqlalchemy.py", line 185, in fromDict
    raise RuntimeError(f"No camera with position {d['Camera Position']}")
RuntimeError: No camera with position None

this isn't really a bug, just an annoyance. I am wondering whether we should make camera position a requirement to add videos to the database- an alternative would be to allow adding them without position info, but to require that info only if the user wants to use Bento for secondary steps like passing data to a pose tracker. If we keep it as-is, the process of populating the databases should at least be made a bit more guided to reduce user frustration.