fix(button-icon): add selected styling to border inverse variant (#3115)

Author: engai

ui/components/button-icons/index.jsx

@@ -40,8 +40,9 @@ class ButtonIcon extends Component {
     } else if (theme === 'inverse') {
       variant = 'slds-button_icon-inverse';
 
-      if (size) {
+      if (size === 'medium') {
         variant = 'slds-button_icon-border-inverse';
+        size = null;
       }
       /**
      * Brand

ui/components/button-icons/stateful/_index.scss

@@ -25,7 +25,8 @@
 .slds-button--icon-container.slds-is-selected,
 .slds-button_icon-border.slds-is-selected,
 .slds-button--icon-border.slds-is-selected,
-.slds-button_icon-border-filled.slds-is-selected {
+.slds-button_icon-border-filled.slds-is-selected,
+.slds-button_icon-border-inverse.slds-is-selected {
   @include button-brand;
 
   .slds-button__icon {