Use sudo-prompt to re-run tsrelay in Linux

[marwan-at-work]

This (draft) PR prompts the user to enter their password for Linux when tsrelay is needed to run with sudo.

Note that for now it assumes Linux already has pkexec installed.
Currently, it keeps the same nonce and port so that we don't need to let the client reconfigure its attributes.

[shayne]

This is all that is visible when running this branch on Linux

[marwan-at-work]

@shayne what do the logs show? And what was your Linux set up?

[shayne]

Was just stock Ubuntu Jammy amd64. Away from keyboard now so I don’t have logs. Were you able to test this in your VM prior to putting up the PR?

[marwan-at-work]

@shayne yep Ubuntu QEMU 7.2 ARM VM:

[shayne]

This is the error

[marwan-at-work]

@shayne thanks for the logs, I think the nonce was being set from an empty variable so I pushed a fix for that. Please try again when you get a chance ✌🏼 thanks!

[shayne]

Follow up.
I tested this today using various distros and desktop environments.

Distros tested:

• Debian
• EndeavourOS (Arch)
• Fedora Silverblue
• linuxmint
• Pop!_OS
• Ubuntu

Desktops environments tested:

• Gnome
• Plasma (KDE)
• Xfce
• LXDE
• Cinnamon
• MATE
• Openbox

Good news:

• If the extension is running as a snap or installed from deb
• and the version of VS Code is new enough
• the password prompt worked across the board (with one exception)

Bad news:

• Unless you're installing from the deb on the VS Code site, the distro version is probably too old for the extension. We should look at supporting older VS Code versions. See Minimum VS Code version #75
• If you're running inside a flatpak the extension doesn't work and puts you in an "Install Tailscale" loop. We should add support for flatpak. See Support Flatpak installations #76
• If you're running Openbox, the authenticator does not work. We do show an error message letting you know. We don't need to address this right now.

cc @samlinville