Get rid of unused class AboutInfo (#882)

Ryujinx/Ui/AboutInfo.cs

@@ -1,9 +0,0 @@
-namespace Ryujinx.Ui
-{
-    internal struct AboutInfo
-    {
-        public string InstallVersion;
-        public string InstallCommit;
-        public string InstallBranch;
-    }
-}

Ryujinx/Ui/AboutWindow.cs

@@ -13,8 +13,6 @@ namespace Ryujinx.Ui
 {
     public class AboutWindow : Window
     {
-        private static AboutInfo AboutInformation { get; set; }
-
 #pragma warning disable CS0649
 #pragma warning disable IDE0044
         [GUI] Window _aboutWin;