Enable dotnet-format test for SB (#46331)

Author: mthalman

src/SourceBuild/content/test/Microsoft.DotNet.SourceBuild.Tests/DotNetFormatTests.cs

@@ -20,8 +20,7 @@ public DotNetFormatTests(ITestOutputHelper outputHelper) : base(outputHelper) {
     /// <Summary>
     /// Format an unformatted project and verify that the output matches the pre-computed solution.
     /// </Summary>
-    // Disabled due to https://github.com/dotnet/roslyn/issues/76797
-    // [Fact]
+    [Fact]
     public void FormatProject()
     {
         if (DotNetHelper.IsMonoRuntime)