efl_ui_widget: make interest_region_mode legacy
summary_:
interest_region_mode makes it possible, that interest_region_get either
returns WIDGET or ITEM coordinates. However, efl-api does not have
items. That means, this can be legacy.
ref T7553
Depends on D8026
Reviewers: woohyun, cedric, Jaehyun_Cho, zmike, segfaultxavi
Reviewed By: segfaultxavi
Subscribers: #reviewers, #committers
Tags: #efl
Maniphest Tasks: T7553
Reviewed-by: Xavi Artigas <xavierartigas@yahoo.es>
Differential Revision: https://phab.enlightenment.org/D8027