Fix hot reload for icon, bell, close on exit; regressed in #16172 (#19217)

In #16172, we removed the propagation of the profile down into the
Terminal Pane Content.

It was holding on to the profile from the _old_ settings model (😱).

This also broke background image hot reload.

(cherry picked from commit 666a75b)
Service-Card-Id: PVTI_lADOAF3p4s4AxadtzgdVVHA
Service-Version: 1.23

Author: DHowett

src/cascadia/TerminalApp/TerminalPaneContent.cpp

@@ -339,8 +339,12 @@ namespace winrt::TerminalApp::implementation
         RestartTerminalRequested.raise(*this, nullptr);
     }
 
-    void TerminalPaneContent::UpdateSettings(const CascadiaSettings& /*settings*/)
+    void TerminalPaneContent::UpdateSettings(const CascadiaSettings& settings)
     {
+        // Reload our profile from the settings model to propagate bell mode, icon, and close on exit mode (anything that uses _profile).
+        const auto profile{ settings.FindProfile(_profile.Guid()) };
+        _profile = profile ? profile : settings.ProfileDefaults();
+
         if (const auto& settings{ _cache.TryLookup(_profile) })
         {
             _control.UpdateControlSettings(settings.DefaultSettings(), settings.UnfocusedSettings());