Revert "ci: disable Collabora's LAVA lab for maintance"

After the merge request !21119 (merged), and when the farm gets back on line, this is prepared to re-enable the farm in the mesa CI.

Do not push before confirmation that Collabora LAVA farm is up again.

Upgrade is expected to occur until 2023-02-06 12:00 GMT (1 PM CET).