Fix mnemonic activation for certificates
Reported here: https://bugzilla.redhat.com/show_bug.cgi?id=2062686#c5
To test: $ ./src/tests/cert-chooser-gtk4 Pressing + repeatedly should focus the certificate chooser buttons, not emit a warning.
Reported here: https://bugzilla.redhat.com/show_bug.cgi?id=2062686#c5
To test: $ ./src/tests/cert-chooser-gtk4 Pressing + repeatedly should focus the certificate chooser buttons, not emit a warning.