Fix qa loader

[heartsucker]

Status

Ready for review

Description of Changes

Fixes #3739

Alter the loader to not start at the index 1 when creating/altering entities. This prevents mangling existing conversations or users.

Testing

• start dev container
• have a conversation with yourself
• docker exec -it $container ./qa_loader.py -m 1
• look at conversation, see no strange messages

Checklist

If you made changes to the server application code:

• Linting (make ci-lint) and tests (make -C securedrop test) pass in the development container

[redshiftzero]

works as advertised!