Preventing checkout request when branch is already checked out

Author: StanleyGoldman

src/UnityExtension/Assets/Editor/GitHub.Unity/UI/BranchesView.cs

@@ -323,6 +323,9 @@ private void OnTreeGUI(Rect rect)
                     if (node.IsFolder)
                         return;
 
+                    if(node.IsActive)
+                        return;
+
                     SwitchBranch(node.Name);
                 },
                 node => {