refactor(segment): revert

Author: thetaPC

core/src/components/segment/test/basic/index.html

@@ -36,7 +36,7 @@
         </ion-toolbar>
 
         <ion-toolbar>
-          <ion-segment value="2" scrollable="true" mode="md">
+          <ion-segment value="2" scrollable="true">
             <ion-segment-button value="1">
               <ion-label>Button 1</ion-label>
             </ion-segment-button>