Fix twitter theme icon colors

src/themes/twitter/elements/button.variables

@@ -22,8 +22,6 @@
 @horizontalPadding: 1.284em;
 @verticalPadding: 0.8571em;
 
-@iconColor: #55ACEE;
-
 @activeBackgroundColor: rgba(0, 0, 0, 0.1);
 
 @primaryColor: @blue;
@@ -43,4 +41,5 @@
 @downPressedShadow: 0px 1px 4px rgba(0, 0, 0, 0.2) inset;
 
 @labeledIconBackgroundColor: rgba(85, 172, 238, 0.05);
-@labeledIconBorder: @borderBoxShadowColor;
+@labeledIconBorder: @borderBoxShadowColor;
+@labeledIconColor: #55ACEE;