Efl.Canvas.Vg.Container: Prevent duplicate transpacency calculation.
If Vg.Container has transparency, this is calculated by _evas_vg_render
in Efl.Canvas.Vg.Object. Therefore, there is no need to propagate
the transparency of the container to the child. _evas_vg_render pre-draws
all children and calculates transparency in batches for avoid duplicate calculation.
Test Plan: N/A
Reviewers: Hermet, kimcinoo, herb
Reviewed By: Hermet
Differential Revision: https://phab.enlightenment.org/D11692