Give t-libs dev-desktop permissions

[thomcc]

I'd like to give myself dev-desktop permissions. I'm on several teams so hopefully this isn't a problem, even though none of them already have it (although it's a bit surprising that this is true for t-libs). Edit: I've changed this to grant dev-desktop to t-libs broadly.

I haven't asked anywhere if this is okay, so let me know if I'm skipping some process.

[compiler-errors]

I think all T-libs deserve access to cloud desktops. If you don't want to amend this PR to make that so, I'll open up a follow-up.

[thomcc]

I've pushed a commit that makes that change, and edited the PR title/desc accordingly. I can easily revert it if this would take much more time to push through, tho (like if it'd take an FCP to grant for libs but not for me, I'd prefer to do it separately, not that I care that much).

[rylev]

r? @jdno