new-calendar-page: add callback for new calendar color chooser

The color chosen in the new calendar page is currently ignored
when creating a new calendar, as described in #681.

Added a callback similar to that used for the name text entry,
allowing new calendars to be created with the chosen color.

Closes https://gitlab.gnome.org/GNOME/gnome-calendar/-/issues/681

src/gui/calendar-management/gcal-new-calendar-page.c

@@ -478,6 +478,14 @@ on_local_calendar_name_entry_text_changed_cb (GtkEntry            *entry,
   update_local_source (self);
 }
 
+static void
+on_local_calendar_color_button_color_changed_cb (GtkColorChooser     *chooser,
+                                                 GParamSpec          *pspec,
+                                                 GcalNewCalendarPage *self)
+{
+  update_local_source (self);
+}
+
 static void
 on_web_description_label_link_activated_cb (GtkLabel            *label,
                                             gchar               *uri,
@@ -653,6 +661,7 @@ gcal_new_calendar_page_class_init (GcalNewCalendarPageClass *klass)
   gtk_widget_class_bind_template_callback (widget_class, on_credential_entry_activate_cb);
   gtk_widget_class_bind_template_callback (widget_class, on_file_chooser_button_file_set_cb);
   gtk_widget_class_bind_template_callback (widget_class, on_local_calendar_name_entry_text_changed_cb);
+  gtk_widget_class_bind_template_callback (widget_class, on_local_calendar_color_button_color_changed_cb);
   gtk_widget_class_bind_template_callback (widget_class, on_url_entry_text_changed_cb);
   gtk_widget_class_bind_template_callback (widget_class, on_web_description_label_link_activated_cb);
 }

src/gui/calendar-management/gcal-new-calendar-page.ui

@@ -70,6 +70,7 @@
             <child>
               <object class="GtkColorButton" id="local_calendar_color_button">
                 <property name="visible">True</property>
+                <signal name="notify::color" handler="on_local_calendar_color_button_color_changed_cb" object="GcalNewCalendarPage" swapped="no" />
               </object>
             </child>