fix: raven boxlite recommends to install pip install raven[sandbox] is sloppy

[mmarras]

Summary

During raven onboarding, choosing the Sandbox isolation gives:

 Run location: Sandbox isolation (boxlite) — isolated in a lightweight VM, safer (needs platform support)
  ⏳ Checking sandbox availability…
  ✗ Sandbox runtime (boxlite) isn't installed.
  Install it, then choose “Retry after install”:  pip install 'raven[sandbox]'

Raven installs via uv, then advising users to gloablly install boxlite via pip install raven[sandbox] is a bit sloppy.

Better is:

uv pip install \
--python "$(head -1 "$(which raven)" | sed 's/^#!//')" \
boxlite

Also annoying that uv tools has a name collision on raven, so uv tool uninstall raven uninstalls raven ai agent if installed via script before, but uv tool install raven gets you something completely different sentry dns.

Steps to reproduce

raven onboard and follow steps until choise for sandbox comes up, then choose sandbox option

Expected behavior

give proper option to install sandbox right away, using proper uv venv isolation, or at least advise users competently

Actual behavior

recommends pip install circumventing uv.

Environment

python without global boxlite installed.

Logs or screenshots