packagekit: Define translated strings once page is ready
packagekit: Define translated strings once page is ready

When it is done too early, then `cockpit.language` is not set up and
strings are not translated.

Closes #13933

moraleslazaro/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,garrett/cockpit,mvollmer/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,mvollmer/cockpit,cockpit-project/cockpit,deryni/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,deryni/cockpit,mvollmer/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,deryni/cockpit,garrett/cockpit,deryni/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpituous/cockpit,garrett/cockpit,deryni/cockpit,garrett/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpituous/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpit-project/cockpit,cockpituous/cockpit,garrett/cockpit