Enable RTL on sample app
Enable RTL on sample app

Summary: The manifest didn't acknowledge that the sample app supports RTL.  Thus `TextView`s didn't render properly.

Reviewed By: emilsjolander

Differential Revision: D4628867

fbshipit-source-id: 72e57f48f7d68a8d2d6dd091b44b9452a3fe281a

facebook/yoga,facebook/yoga,facebook/yoga,yihuang/css-layout,yihuang/css-layout,yihuang/css-layout,facebook/css-layout,yihuang/css-layout,facebook/yoga,yihuang/css-layout,facebook/yoga,yihuang/css-layout,facebook/yoga,facebook/yoga,yihuang/css-layout,facebook/yoga,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/css-layout,yihuang/css-layout,facebook/css-layout,yihuang/css-layout,yihuang/css-layout,facebook/css-layout,facebook/css-layout,facebook/css-layout,facebook/css-layout,facebook/css-layout