Guarding on `[ ! -d "$VENV_DIR" ]` treats an interrupted create (no
bin/activate) and an interpreter upgrade (dangling bin/python3) as a
good venv, so the script dies in `source venv/bin/activate` and the only
fix is knowing to delete the directory. Probe that the venv runs, and
rebuild with --clear to relink the interpreter.
Also install requirements unconditionally, which is cheap. The license
verifier skipped the install whenever the venv already existed, so it
passed without ever seeing a newly added dependency.
Fixes failure encountered by @ahmedtd. Not filing an issue because this
is pretty trivial.
AI-assisted.