paseo agent open launched Desktop with whatever string it was given,
printed "opened" and exited 0, so a bad ID moved the user to a broken
"Agent not found" tab and the calling script saw success. Look the agent
up on the daemon first, the way inspect and mode do, and open Desktop on
the ID the daemon resolved.
Closes#5721
Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>
