Tests for collection signing...

feature was added in https://issues.redhat.com/browse/AAH-1059, https://issues.redhat.com/browse/AAH-1061, https://issues.redhat.com/browse/AAH-1062, https://issues.redhat.com/browse/AAH-1264, https://issues.redhat.com/browse/AAH-1333

but there are no tests - fix that

(This will involve using cy.settings to enable signing for those tests.)

(if we have insights mode testin when this is being done, also include tests for https://github.com/ansible/ansible-hub-ui/pull/1892)