For #21973 - Remove @color/add_on_private_browsing_exterior_circle_background_dark_theme redirection

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

@@ -40,7 +40,7 @@
     <color name="onboarding_card_background_end_gradient_normal_theme">@color/accent_high_contrast_dark_theme</color>
     <color name="onboarding_illustration_selected_normal_theme">@color/accent_dark_theme</color>
     <color name="onboarding_illustration_deselected_normal_theme">@color/onboarding_illustration_deselected_dark_theme</color>
-    <color name="add_on_private_browsing_exterior_circle_background_normal_theme">@color/add_on_private_browsing_exterior_circle_background_dark_theme</color>
+    <color name="add_on_private_browsing_exterior_circle_background_normal_theme">@color/accent_dark_theme</color>
     <color name="add_on_private_browsing_interior_icon_background_normal_theme">@color/add_on_private_browsing_interior_icon_background_dark_theme</color>
     <color name="prompt_login_edit_text_cursor_color_normal_theme">@color/prompt_login_edit_text_cursor_color_dark_theme</color>
     <color name="readermode_start_gradient_normal_theme">@color/photonViolet30</color>

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

@@ -31,7 +31,6 @@
     <color name="accent_bright_dark_theme">@color/photonViolet70</color>
     <color name="accent_high_contrast_dark_theme">@color/photonViolet40</color>
     <color name="onboarding_illustration_deselected_dark_theme">#99FBFBFE</color>
-    <color name="add_on_private_browsing_exterior_circle_background_dark_theme">@color/accent_dark_theme</color>
     <color name="add_on_private_browsing_interior_icon_background_dark_theme">@color/photonWhite</color>
     <color name="prompt_login_edit_text_cursor_color_dark_theme">@color/photonViolet50</color>
     <color name="search_suggestion_indicator_icon_color_dark_theme">@color/photonGreen60</color>