Fixes font size issue

## Issue
By using the invalid `apx` value, apps must be built or use the runtime LESS compiler in order to render correctly.

## Fix
By duplicating the font-size property with both `px` and `apx`, the former ensures that debug-mode apps work (because `apx` is ignored as invalid) and built apps work because the converted `apx` value overrides the converted `px` value.

Enyo-DCO-1.1-Signed-off-by: Ryan Duffy (ryan.duffy@lge.com)