update: sib-chat css hd

sib-chat.js

@@ -45,7 +45,7 @@ export const SibChat = {
         mode: "open"
       });
       this.element.shadowRoot.append(...Helpers.importCSS(
-        'https://unpkg.com/@startinblox/component-chat/themes/converse-hd-extended.css',
+        'https://unpkg.com/converse.js@5.0/dist/converse.css',
         'https://unpkg.com/@startinblox/component-chat/themes/converse-hd.css'
       ));
       if (window.converse_sib === undefined) {
@@ -54,10 +54,6 @@ export const SibChat = {
     } // Else, not logged in on page load (even if not on chat)
   },
 
-  empty() {
-    this.element.innerHTML = '';
-  },
-
   async populate() {
     if(typeof converse_sib !== 'undefined') {
       await converse_sib.loaded_deferred;