elm: make elm_layout_text_set use efl_text_markup_set

elm: make elm_layout_text_set use efl_text_markup_set

The elm_layout_text_get is using efl_text_markup_get by following commit.

    commit c07a40c745c5df1b1f6f0bbf666b233d8d072ca7
    elm: make elm_object_text_get return markup info as well.

    This commit solves following issue

    https://phab.enlightenment.org/T6642

    If I set object text as below
    elm_object_text_set(btn, "Some<br>text");
    then elm_object_text_get(btn) returns "Some text" not "Some<br>text".

So using efl_text_markup_set makes sense.