Option to toggle the system tray icon (#23220)

* Added option to toggle the system tray icon

At the moment, this hides the icon making the settings window inaccessible without first modifying the general `settings.json` file.

* Use IPC messages to manage the tray icon settings

* Fix launching second window binds to active settings process

* Added context menu option to hide tray icon

* Added Exit PT button to settings ui NavigationView.PaneFooter

* Moved DllImports to NativeMethods.cs

* Sentence case titles

* Fix whitespace

* Re-add exit icon to NavView

* Re-added toggle switch to new UI

* Fix build

* Fix build after merge main

* Fix the string to display

* add shut down buttons

* finish polish

* fix string

* Styling tweaks to titlebar and settingscards

* fix comment

* fix unit test

* fix ut

---------

Co-authored-by: Jaime Bernardo <jaime@janeasystems.com>
Co-authored-by: vanzue <vanzue@outlook.com>
Co-authored-by: Kayla Cinnamon <cinnamon@microsoft.com>
Co-authored-by: Niels Laute <niels.laute@live.nl>

src/settings-ui/Settings.UI.Library/GeneralSettings.cs

@@ -19,6 +19,10 @@ namespace Microsoft.PowerToys.Settings.UI.Library
         [JsonPropertyName("startup")]
         public bool Startup { get; set; }
 
+        // Gets or sets a value indicating whether the powertoys system tray icon should be hidden.
+        [JsonPropertyName("show_tray_icon")]
+        public bool ShowSysTrayIcon { get; set; }
+
         // Gets or sets a value indicating whether the powertoy elevated.
         [CmdConfigureIgnoreAttribute]
         [JsonPropertyName("is_elevated")]
@@ -75,6 +79,7 @@ namespace Microsoft.PowerToys.Settings.UI.Library
         public GeneralSettings()
         {
             Startup = false;
+            ShowSysTrayIcon = true;
             IsAdmin = false;
             EnableWarningsElevatedApps = true;
             IsElevated = false;