add a setup finished screen

added the ability to hide the help button (basically just for the finish screen, because it has a bigger discord button in the same place)
holding shift while opening the setup wizard now opens it in passive mode, aka it will install only what you need. this is mostly for testing and likely will be nuked before this code as a whole is made part of the official emulator, but it might not

src/Ryujinx/UI/SetupWizard/Pages/Final/SetupFinishedPageContext.cs

@@ -0,0 +1,13 @@
+using Gommon;
+using Ryujinx.Ava.Common.Locale;
+
+namespace Ryujinx.Ava.UI.SetupWizard.Pages
+{
+    public class SetupFinishedPageContext() : SetupWizardPageContext(LocaleKeys.SetupWizardFinalPageTitle)
+    {
+        public override LocaleKeys ActionContent => LocaleKeys.SetupWizardFinalPageAction;
+
+        // informative step; this implementation is not called.
+        public override Result CompleteStep() => Result.Success;
+    }
+}