For #23287 - Replace @color/tab_tray_item_divider_normal_theme with @color/fx_mobile_border_color_default

app/src/main/res/layout/component_tabstray2.xml

@@ -127,7 +127,7 @@
         android:id="@+id/divider"
         android:layout_width="0dp"
         android:layout_height="1dp"
-        android:background="@color/tab_tray_item_divider_normal_theme"
+        android:background="@color/fx_mobile_border_color_default"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/info_banner" />

app/src/main/res/layout/tab_tray_grid_item.xml

@@ -28,7 +28,7 @@ A FrameLayout here is an efficient way of having a views stack while allowing:
         app:cardBackgroundColor="@color/fx_mobile_layer_color_2"
         app:cardCornerRadius="@dimen/tab_tray_grid_item_border_radius"
         app:cardElevation="0dp"
-        app:strokeColor="@color/tab_tray_item_divider_normal_theme"
+        app:strokeColor="@color/fx_mobile_border_color_default"
         app:strokeWidth="1dp">
 
         <androidx.constraintlayout.widget.ConstraintLayout
@@ -84,7 +84,7 @@ A FrameLayout here is an efficient way of having a views stack while allowing:
                 android:id="@+id/horizonatal_divider"
                 android:layout_width="match_parent"
                 android:layout_height="1dp"
-                android:background="@color/photonLightGrey30"
+                android:background="@color/fx_mobile_border_color_default"
                 app:layout_constraintTop_toBottomOf="@+id/mozac_browser_tabstray_title" />
 
             <androidx.cardview.widget.CardView

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

@@ -90,7 +90,7 @@
 
     <!-- Border -->
     <!-- Default, Divider, Dotted -->
-    <color name="fx_mobile_border_color_default" tools:ignore="UnusedResources">@color/photonDarkGrey05</color>
+    <color name="fx_mobile_border_color_default">@color/photonDarkGrey05</color>
     <!-- Onboarding -->
     <color name="fx_mobile_border_color_inverted" tools:ignore="UnusedResources">@color/photonLightGrey30</color>
     <!-- Form parts -->
@@ -136,7 +136,6 @@
     <!-- Tab tray -->
     <color name="tab_tray_item_background_normal_theme">@color/photonDarkGrey80</color>
     <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_heading_icon_inactive_normal_theme">@color/photonLightGrey05</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

@@ -90,7 +90,7 @@
 
     <!-- Border -->
     <!-- Default, Divider, Dotted -->
-    <color name="fx_mobile_border_color_default" tools:ignore="UnusedResources">@color/photonLightGrey30</color>
+    <color name="fx_mobile_border_color_default">@color/photonLightGrey30</color>
     <!-- Onboarding -->
     <color name="fx_mobile_border_color_inverted" tools:ignore="UnusedResources">@color/photonDarkGrey05</color>
     <!-- Form parts -->
@@ -203,7 +203,6 @@
     <!-- Tab tray -->
     <color name="tab_tray_item_background_normal_theme">@color/photonLightGrey10</color>
     <color name="tab_tray_item_selected_background_normal_theme">#E5DFF4</color>
-    <color name="tab_tray_item_divider_normal_theme">@color/photonLightGrey30</color>
     <color name="tab_tray_heading_icon_inactive_normal_theme">@color/photonInk20A48</color>
     <color name="tab_tray_heading_icon_menu_normal_theme">@color/accent_normal_theme</color>
     <color name="tab_tray_item_thumbnail_background_normal_theme">@color/photonLightGrey10</color>