Make the action of the recipient key input field always trigger the
details dialog of the current certificate or group (if there is one).
Note: This action is not accessible via keyboard or for screen readers,
but that's okay because the details dialog can also be opened via the
context menu.

Moreover, use only emblem-* icons for the action to give the different
statuses a unified look.

GnuPG-bug-id: 5845