[meta]common csproj/vcxproj settings to Directory.Build.props (#17067)

* Add common csproj/vcxproj settings to Directory.Build.props

* Set TreatWarningsAsErrors to true for all c# projects

* Minor fixes in unit test projects where Analyzers where not enabled before

* Clean up Directory.Build.props

* Remove properties from ImageResizer csprojs files

src/modules/launcher/Plugins/Microsoft.Plugin.Folder.UnitTests/DriveOrSharedFolderTests.cs

@@ -93,11 +93,11 @@ namespace Microsoft.Plugin.Folder.UnitTests
             // Assert
             if (hasValues)
             {
-                Assert.IsTrue(results.Count() > 0);
+                Assert.IsTrue(results.Any());
             }
             else
             {
-                Assert.IsTrue(results.Count() == 0);
+                Assert.IsFalse(results.Any());
             }
         }
     }