Ignore access denied to set run on startup

If the user doesn't have write access (or their AV is preventing access)
to SOFTWARE\Microsoft\Windows\CurrentVersion\Run, ignore the problem
gracefully instead of crashing.

Classes/OsUtils.cs

@@ -183,7 +183,17 @@ internal static bool CompositionEnabled()
 
         internal static void ApplyRunOnStartup()
         {
-            RegistryKey runKey = Registry.CurrentUser.CreateSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run");
+            RegistryKey runKey;
+
+            try
+            {
+                runKey = Registry.CurrentUser.CreateSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run");
+            }
+            catch (UnauthorizedAccessException)
+            {
+                // Access denied by non-standard ACL or antivirus
+                return;
+            }
 
             if (Settings.RunOnStartup)
             {