Disable support for running PowerShell scripts in Add Package Reference dialog.

src/AddIns/Misc/PackageManagement/Project/Src/ProcessPackageAction.cs

@@ -40,7 +40,9 @@ namespace ICSharpCode.PackageManagement
 		public void Execute()
 		{
 			BeforeExecute();
-			using (RunPackageScriptsAction runScriptsAction = CreateRunPackageScriptsAction()) {
+			if (PackageScriptSession != null) {
+				ExecuteWithSession();
+			} else {
 				ExecuteCore();
 			}
 		}
@@ -52,6 +54,13 @@ namespace ICSharpCode.PackageManagement
 			GetPackageIfMissing();
 		}
 		
+		void ExecuteWithSession()
+		{
+			using (RunPackageScriptsAction runScriptsAction = CreateRunPackageScriptsAction()) {
+				ExecuteCore();
+			}
+		}
+		
 		RunPackageScriptsAction CreateRunPackageScriptsAction()
 		{
 			return CreateRunPackageScriptsAction(PackageScriptSession, Project);

src/AddIns/Misc/PackageManagement/Test/Src/ProcessPackageActionTests.cs

@@ -84,6 +84,7 @@ namespace PackageManagement.Tests
 			CreateAction();
 			var expectedProject = new FakePackageManagementProject();
 			action.Project = expectedProject;
+			action.PackageScriptSession = new FakePackageScriptSession();
 			action.Execute();
 			
 			var actualProject = action.ProjectPassedToCreateRunPackageScriptsAction;
@@ -95,9 +96,19 @@ namespace PackageManagement.Tests
 		public void Execute_MethodCalled_RunPackageScriptsActionIsDisposed()
 		{
 			CreateAction();
+			action.PackageScriptSession = new FakePackageScriptSession();
 			action.Execute();
 			
 			Assert.IsTrue(action.IsRunPackageScriptsActionDisposed);
 		}
+		
+		[Test]
+		public void Execute_NullSession_RunPackageScriptsActionIsNotCreated()
+		{
+			CreateAction();
+			action.Execute();
+			
+			Assert.IsFalse(action.IsRunPackageScriptsActionCreated);
+		}
 	}
 }