[fxcop] Settings UI (#7559)

* Remove redundant default initializations

* Implement IDisposable in HotkeySettingsControl

* Mark classes and methods as static

* Move Interop.ShowWindow to NativeMethods class

* Fix string-related warnings

* Remove unused argument for KeyEventHandler

* Log caught general exceptions

* Use safe navigation operator for null argument checks

* Suppress CA2007 warnings and enable FxCop

* Suppress warning for unused event handler params

* Use TryParse in ImageResizerPage

* Use ConfigureAwait(false) for CA2007

src/core/Microsoft.PowerToys.Settings.UI/Interop.cs

@@ -23,9 +23,6 @@ namespace Microsoft.PowerToys.Settings.UI
             }
         }
 
-        [DllImport("user32.dll")]
-        public static extern bool ShowWindow(System.IntPtr hWnd, int nCmdShow);
-
         [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Interop naming consistancy")]
         public const int SW_HIDE = 0;
     }