elementary: Check for valid focus manager before starting do loop
Apparently there are cases where efl_ui_focus_object_focus_manager_get
can return NULL. In order to trap for this, we can simply modify the
do loop slightly and check for a valid manager before we actually
start looping
Test Case: elementary_test -to "Panel Scrollable" and click Toggle
button
ref T7030
Differential Revision: https://phab.enlightenment.org/D6704