fixed theme-ionic test page for sizes

Author: BenOsodrac

core/src/components/button/test/theme-ionic/index.html

@@ -34,7 +34,7 @@ <h4>Preview options</h4>
 
         <p>
           <ion-select id="select-size" justify="space-between" interface="alert" label="Size" placeholder="">
-            <ion-select-option selected="true" value="">default</ion-select-option>
+            <ion-select-option selected="true" value="medium">Medium</ion-select-option>
             <ion-select-option value="small">Small</ion-select-option>
             <ion-select-option value="large">Large</ion-select-option>
           </ion-select>