Ui improvements (#6651)

* PLT-6691 - Centering emoji in post view

* PLT-6737 - FIxing on hover style for heade icons

* PLT-6768 - Fixing error on profile picture

* PLT-6792 - Fixing link preview image not resizing

* PLT-6793 - User popover position on mobile

webapp/components/user_profile.jsx

@@ -56,6 +56,11 @@ export default class UserProfile extends React.Component {
     render() {
         let name = '...';
         let profileImg = '';
+        let popoverPosition = 'right';
+        if (Utils.isMobile()) {
+            popoverPosition = 'bottom';
+        }
+
         if (this.props.user) {
             name = Utils.displayUsername(this.props.user.id);
             profileImg = Client.getUsersRoute() + '/' + this.props.user.id + '/image?time=' + this.props.user.last_picture_update;
@@ -73,7 +78,7 @@ export default class UserProfile extends React.Component {
             <OverlayTrigger
                 ref='overlay'
                 trigger='click'
-                placement='right'
+                placement={popoverPosition}
                 rootClose={true}
                 overlay={
                     <ProfilePopover