MC-15083: Resolve performance issues

- Do not double load “Open Sans”, it’s already imported by the core application

Author: davemacaulay

app/code/Magento/PageBuilder/view/adminhtml/web/css/source/form/element/tinymce.css

@@ -3,34 +3,6 @@
  * See COPYING.txt for license details.
  */
 
-@font-face {
-    font-family: "Open Sans";
-    font-style: normal;
-    font-weight: 300;
-    src: url('../../../../fonts/opensans/light/opensans-300.woff2') format('woff2'), url('../../../../fonts/opensans/light/opensans-300.woff') format('woff');
-}
-
-@font-face {
-    font-family: "Open Sans";
-    font-style: normal;
-    font-weight: 400;
-    src: url('../../../../fonts/opensans/regular/opensans-400.woff2') format('woff2'), url('../../../../fonts/opensans/regular/opensans-400.woff') format('woff');
-}
-
-@font-face {
-    font-family: "Open Sans";
-    font-style: normal;
-    font-weight: 600;
-    src: url('../../../../fonts/opensans/semibold/opensans-600.woff2') format('woff2'), url('../../../../fonts/opensans/semibold/opensans-600.woff') format('woff');
-}
-
-@font-face {
-    font-family: "Open Sans";
-    font-style: normal;
-    font-weight: 700;
-    src: url('../../../../fonts/opensans/bold/opensans-700.woff2') format('woff2'), url('../../../../fonts/opensans/bold/opensans-700.woff') format('woff');
-}
-
 h1 {
     color: #333;
     font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;