Merge pull request #10524 from overleaf/jel-cms-btn

[web] Add new button type to CMS pages

GitOrigin-RevId: fc7c21e936c3ce2a6092a3f62bfcbc78d3c0d2c2

services/web/frontend/stylesheets/core/page-style.less

@@ -1,7 +1,7 @@
 .page-style {
   background-color: @white;
 
-  a {
+  a:not(.btn) {
     text-decoration: underline;
   }