efl: Ensure pinentry window is activated.

* efl/pinentry-efl.c (create_window): Call elm_win_activate.

This ensure the new window displayed on screen is grabbed/focused and
PIN is entered in the newly created window rather than shell or
application with active focus which can lead to accidental PIN leak.

• Signed-off-by: Damien Goutte-Gattat <dgouttegattat@incenp.org>