Proxy token expires too quickly when building snaps

[Isaac True]

When building large, long-running (>=6 hours) snaps on Launchpad, the proxy token can expire before the build has been completed, causing "407 Proxy Authentication Required" HTTP errors in software that try to access the internet. This is particularly a problem on architectures with slower builders like riscv64, where a build can take many times longer than it would on amd64 or arm64.

It would be great if this token could be extended, or if another mechanism could be put in place to manage internet access during the snap builds.

Example of a failed build that took too long causing the token to expire: https://launchpadlibrarian.net/701095095/buildlog_snap_ubuntu_jammy_riscv64_iotdevice-device-ui_BUILDING.txt.gz

The same build succeeding on amd64: https://launchpadlibrarian.net/701189377/buildlog_snap_ubuntu_jammy_amd64_iotdevice-device-ui-test_BUILDING.txt.gz

[Jürgen Gmach (jugmac00)]

see https://chat.canonical.com/canonical/pl/zsawgszms3ftirakudffhmzyma (internal) for more context