Stop updating AutoSuggestBox on selection (#17961)

`AutoSuggestBox` has a `SuggestionChosen` event and any reasonable
person would assume that this means one of the items was chosen.
But with WinUI it's raised whenever a suggestion is merely highlighted.
`QuerySubmitted` is the right event instead. Clearly that naming is
a lot better than `SuggestionChosen`, since the property to get the
chosen item is called `ChosenSuggestion`.
WinUI, like the unrelenting wilderness of a world indifferent to human
suffering, stands as a testament to the futility of human aspiration.

Closes #17916

## Validation Steps Performed
* Type "Casc"
* Move up/down with the arrow keys
* Neither the filtered list nor the text updates ✅
* Press Enter on an item
* Text updates ✅

(cherry picked from commit bcac999)
Service-Card-Id: PVTI_lADOAF3p4s4AmhmQzgTW9-o
Service-Version: 1.22

src/cascadia/TerminalSettingsEditor/Appearances.cpp

@@ -1030,9 +1030,9 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         }
     }
 
-    void Appearances::FontFaceBox_SuggestionChosen(const AutoSuggestBox& sender, const AutoSuggestBoxSuggestionChosenEventArgs& args)
+    void Appearances::FontFaceBox_QuerySubmitted(const AutoSuggestBox& sender, const AutoSuggestBoxQuerySubmittedEventArgs& args)
     {
-        const auto font = unbox_value<Editor::Font>(args.SelectedItem());
+        const auto font = unbox_value<Editor::Font>(args.ChosenSuggestion());
         const auto fontName = font.Name();
         auto fontSpec = sender.Text();
 

src/cascadia/TerminalSettingsEditor/Appearances.h

@@ -179,7 +179,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
 
         void FontFaceBox_GotFocus(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
         void FontFaceBox_LostFocus(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
-        void FontFaceBox_SuggestionChosen(const winrt::Windows::UI::Xaml::Controls::AutoSuggestBox&, const winrt::Windows::UI::Xaml::Controls::AutoSuggestBoxSuggestionChosenEventArgs&);
+        void FontFaceBox_QuerySubmitted(const winrt::Windows::UI::Xaml::Controls::AutoSuggestBox&, const winrt::Windows::UI::Xaml::Controls::AutoSuggestBoxQuerySubmittedEventArgs&);
         void FontFaceBox_TextChanged(const winrt::Windows::UI::Xaml::Controls::AutoSuggestBox&, const winrt::Windows::UI::Xaml::Controls::AutoSuggestBoxTextChangedEventArgs&);
         void DeleteFontKeyValuePair_Click(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
         safe_void_coroutine BackgroundImage_Click(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);

src/cascadia/TerminalSettingsEditor/Appearances.xaml

@@ -214,10 +214,11 @@
                                     ItemTemplate="{StaticResource FontFaceComboBoxItemTemplate}"
                                     ItemsSource="{x:Bind FilteredFontList, Mode=OneWay}"
                                     LostFocus="FontFaceBox_LostFocus"
-                                    SuggestionChosen="FontFaceBox_SuggestionChosen"
+                                    QuerySubmitted="FontFaceBox_QuerySubmitted"
                                     Text="{x:Bind Appearance.FontFace, Mode=OneWay}"
                                     TextBoxStyle="{StaticResource TextBoxSettingStyle}"
-                                    TextChanged="FontFaceBox_TextChanged" />
+                                    TextChanged="FontFaceBox_TextChanged"
+                                    UpdateTextOnSelect="False" />
                     <CheckBox x:Name="ShowAllFontsCheckbox"
                               x:Uid="Profile_FontFaceShowAllFonts"
                               IsChecked="{x:Bind ShowAllFonts, Mode=TwoWay}" />