[fenix] For https://github.com/mozilla-mobile/fenix/issues/22839 - Remove @color/tab_tray_heading_icon_dark_theme redirection

app/src/main/res/values-night/colors.xml

@@ -147,7 +147,7 @@
     <color name="tab_tray_item_selected_background_normal_theme">@color/tab_tray_item_selected_background_dark_theme</color>
     <color name="tab_tray_item_divider_normal_theme">@color/photonDarkGrey10</color>
     <color name="tab_tray_item_media_background_normal_theme">@color/photonViolet50</color>
-    <color name="tab_tray_heading_icon_normal_theme">@color/tab_tray_heading_icon_dark_theme</color>
+    <color name="tab_tray_heading_icon_normal_theme">@color/photonViolet50</color>
     <color name="tab_tray_heading_icon_inactive_normal_theme">@color/tab_tray_heading_icon_inactive_dark_theme</color>
     <color name="tab_tray_heading_icon_menu_normal_theme">@color/photonLightGrey05</color>
     <color name="tab_tray_item_thumbnail_background_normal_theme">@color/photonDarkGrey50</color>

app/src/main/res/values/colors.xml

@@ -156,7 +156,6 @@
 
     <!-- Tab Tray -->
     <color name="tab_tray_item_selected_background_dark_theme">#412E69</color>
-    <color name="tab_tray_heading_icon_dark_theme">@color/photonViolet50</color>
     <color name="tab_tray_heading_icon_inactive_dark_theme">@color/photonLightGrey05</color>
 
     <!-- Private theme color palette -->