[fenix] For https://github.com/mozilla-mobile/fenix/issues/23240 - Replace @color/contrast_text_private_theme with @color/fx_mobile_private_text_color_primary

@color/contrast_text_private_theme and @color/fx_mobile_private_text_color_primary are the same color

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

@@ -32,7 +32,7 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"
             app:srcCompat="@drawable/ic_info"
-            tools:tint="@color/contrast_text_private_theme" />
+            tools:tint="@color/fx_mobile_private_text_color_primary" />
 
         <TextView
             android:id="@+id/title"

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

@@ -145,7 +145,6 @@
 
     <!-- Private theme color palette -->
     <color name="secondary_text_private_theme">#A7A2B7</color>
-    <color name="contrast_text_private_theme">@color/photonLightGrey05</color>
     <color name="caption_text_private_theme">@color/photonLightGrey70</color>
     <color name="foundation_private_theme">#261E4B</color>
     <color name="inset_private_theme">@color/photonInk50</color>

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

@@ -230,7 +230,7 @@
         <!-- Updated color attributes -->
         <item name="primaryText">@color/fx_mobile_private_text_color_primary</item>
         <item name="secondaryText">@color/secondary_text_private_theme</item>
-        <item name="contrastText">@color/contrast_text_private_theme</item>
+        <item name="contrastText">@color/fx_mobile_private_text_color_primary</item>
         <item name="accent">@color/accent_private_theme</item>
         <item name="accentBright">@color/accent_bright_private_theme</item>
         <item name="accentHighContrast">@color/accent_high_contrast_private_theme</item>