Replace plus with add_circle icons

apps/app/src/components/Bookmarks/BookmarkFolderTree.module.scss

@@ -24,10 +24,6 @@ $grw-bookmark-item-padding-left: 35px;
 
 .grw-foldertree :global {
 
-  .btn-page-item-control .icon-plus::before {
-    font-size: 18px;
-  }
-
   .list-group-item {
     .grw-visible-on-hover {
       display: none;

apps/app/src/components/ItemsTree/ItemsTree.module.scss

@@ -17,11 +17,6 @@ $grw-pagetree-item-container-height: 40px;
   }
 
   :global {
-    .btn-page-item-control {
-      .icon-plus::before {
-        font-size: 18px;
-      }
-    }
 
     .list-group-item {
       .grw-visible-on-hover {

apps/app/src/components/Me/ExternalAccountLinkedMe.jsx

@@ -64,7 +64,7 @@ class ExternalAccountLinkedMe extends React.Component {
             className="btn btn-outline-secondary btn-sm pull-right"
             onClick={this.openAssociateModal}
           >
-            <i className="icon-plus" aria-hidden="true" />
+            <span className="material-symbols-outlined" aria-hidden="true">add_circle</span>
             Add
           </button>
           { t('admin:user_management.external_accounts') }

apps/app/src/components/TreeItem/NewPageInput/NewPageCreateButton.tsx

@@ -27,7 +27,7 @@ export const NewPageCreateButton: FC<NewPageCreateButtonProps> = (props) => {
               className="border-0 rounded btn btn-page-item-control p-0 grw-visible-on-hover"
               onClick={onClick}
             >
-              <i className="icon-plus d-block p-0" />
+              <span className="material-symbols-outlined d-block p-0">add_circle</span>
             </button>
           </NotAvailableForReadOnlyUser>
         </NotAvailableForGuest>