Messaging: res: color: Use brighter color for fab

Change-Id: Id2c6d382b5eff4811897d9157dd165ec289b188e

res/values/colors.xml

@@ -142,7 +142,7 @@
     <color name="people_and_options_header_text">#6d6d6d</color>
     <color name="people_and_options_list_divider">#cccccc</color>
 
-    <color name="fab_color">@color/lineage_accent</color>
+    <color name="fab_color">@*android:color/system_accent1_500</color>
     <color name="fab_pressed_color">@*android:color/primary_device_default_light</color>
     <color name="fab_ripple">#40ffffff</color>