themes: Rename "dragable" to "draggable"
"Dragable" is a misspelling:
We have it EVERYWHERE in EFL, even with jokes:
This patch only fixes the theme API so it does not get carved in stone for this release.
Depends on D10217
Test Plan: No functional changes.
Reviewed By: zmike
Differential Revision: https://phab.enlightenment.org/D10218