Pass nologo to MSBuild in 'add package' command

Fixes #6534

src/dotnet/commands/dotnet-add/dotnet-add-package/Program.cs

@@ -100,6 +100,9 @@ namespace Microsoft.DotNet.Tools.Add.PackageReference
             // Turn off restore for Dotnet cli tool references so that we do not generate extra dg specs
             args.Add($"/p:RestoreDotnetCliToolReferences=false");
 
+            // Output should not include MSBuild version header
+            args.Add("/nologo");
+
             var result = new MSBuildForwardingApp(args).Execute();
 
             if (result != 0)

test/dotnet-add-package.Tests/GivenDotnetPackageAdd.cs

@@ -116,6 +116,27 @@ namespace Microsoft.DotNet.Cli.Package.Add.Tests
             cmd.StdErr.Should().BeEmpty();
         }
 
+        [Fact]
+        public void WhenValidPackageIsPassedMSBuildDoesNotPrintVersionHeader()
+        {
+            var testAsset = "TestAppSimple";
+            var projectDirectory = TestAssets
+                .Get(testAsset)
+                .CreateInstance()
+                .WithSourceFiles()
+                .Root
+                .FullName;
+
+            var packageName = "Newtonsoft.Json";
+            var packageVersion = "9.0.1";
+            var cmd = new DotnetCommand()
+                .WithWorkingDirectory(projectDirectory)
+                .ExecuteWithCapturedOutput($"add package {packageName} --version {packageVersion}");
+            cmd.Should().Pass();
+            cmd.StdOut.Should().NotContain("Microsoft (R) Build Engine version");
+            cmd.StdErr.Should().BeEmpty();
+        }
+
         [Fact]
         public void WhenMultiplePackagesArePassedCommandFails()
         {