[Elm_Entry] Fix bug: magnifier position is incorrect when mouse down on selection...

[Elm_Entry] Fix bug: magnifier position is incorrect when mouse down on selection handler

Summary:
Magnifier is displayed incorrectly when mouse down on selection handler

Reproduce way: Right click on entry (eg Entry), choose Select, select some text, press left mouse
on selection handler (do not move the mouse), take a look at magnifier position.
Reason: Magnifier position is set to mouse down position in entry.
Fix: Check mouse down status and place correct position for magnifier.

Reviewers: seoz, Hermet

Reviewed By: Hermet

Differential Revision: https://phab.enlightenment.org/D573