Removed margin from ScrollViewer in TextBox style
Removed margin from ScrollViewer in TextBox style

Fixes #1800
jumulr/MahApps.Metro,chuuddo/MahApps.Metro,batzen/MahApps.Metro,psinl/MahApps.Metro,Danghor/MahApps.Metro,p76984275/MahApps.Metro,pfattisc/MahApps.Metro,ye4241/MahApps.Metro,Evangelink/MahApps.Metro,MahApps/MahApps.Metro,Jack109/MahApps.Metro,xxMUROxx/MahApps.Metro