Use 12,12 margin for clone dialog

Author: jcansdale

src/GitHub.VisualStudio.UI/Views/Dialog/Clone/RepositoryCloneView.xaml

@@ -9,6 +9,7 @@
              xmlns:vs="clr-namespace:Microsoft.VisualStudio.PlatformUI;assembly=Microsoft.VisualStudio.Shell.14.0"
              Background="{DynamicResource {x:Static vs:EnvironmentColors.ToolWindowBackgroundBrushKey}}"
              Foreground="{DynamicResource {x:Static vs:EnvironmentColors.ToolWindowTextBrushKey}}"
+             Margin="12,12"
              mc:Ignorable="d" d:DesignHeight="414" d:DesignWidth="440">
     <d:DesignData.DataContext>
         <ghfvs:RepositoryCloneViewModelDesigner/>