test: Make "check for updates" button selector more specific
test: Make "check for updates" button selector more specific

Since the tracer integration, the Status card can contain other buttons,
like "Restart services".

Also drop a bogus wait_in_text() and a redundant wait_visible()
invocation.

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