elm_multibuttonentry: send "clicked" signal when item got hardware enter key.
Summary:
It was kind of bug state before.
There was no any action when the user gives a focus on an item. then press the enter key.
The item should be set as selected state after that should call clicked signal.
@fix
Test Plan: elementary test MBE sample.
Reviewers: woohyun, bu5hm4n, Hermet
Subscribers: cedric, jpeg
Differential Revision: https://phab.enlightenment.org/D4368
Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>