Fix .NET managed permission event test

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: joshspicer

dotnet/test/Unit/PermissionHandlerTests.cs

@@ -36,7 +36,8 @@ public void PermissionEventExposesManagedApprovalRequired()
             SerializerOptions);
 
         Assert.NotNull(data);
-        Assert.True(data.PermissionRequest.ManagedApprovalRequired);
+        var request = Assert.IsType<PermissionRequestRead>(data.PermissionRequest);
+        Assert.True(request.ManagedApprovalRequired);
     }
 
     [Fact]