test: Clean up #last-checked selector in TestUpdates
test: Clean up #last-checked selector in TestUpdates

THis is already an ID, no need to nest it.

martinpitt/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,garrett/cockpit,cockpit-project/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,garrett/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,garrett/cockpit