remove unused color value

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

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

@@ -89,6 +89,4 @@
     <!-- voicemessage -->
     <color name="nc_voice_message_outgoing_controls">#606060</color>
 
-    <color name="camera_bg_tint">#99121212</color>
-
 </resources>