elementary: Avoid passing NULL in some win focus methods
Summary:
This one is rather harmless, as the NULL returned by this fuction is handled
correctly in all places, but this commit removes the runtime warning.
ref T7030
Test Plan: After this commit the warning disappears. Got the warning with win_example.
Reviewers: zmike, bu5hm4n, devilhorns
Reviewed By: devilhorns
Subscribers: netstar, cedric, committers
Tags: efl
Maniphest Tasks: T7030
Differential Revision: https://phab.enlightenment.org/D6538