Merge pull request #10105 from overleaf/ii-rich-text-scroll-bar

[web] Scroll bar invisible in rich text mode

GitOrigin-RevId: 48ffabb207dbecf73eb6b00b2cf5b6047d9539a7

services/web/frontend/stylesheets/vendor/codemirror.css

@@ -181,7 +181,7 @@ div.CodeMirror span.CodeMirror-nonmatchingbracket {color: #a22;}
    flickering artifacts. */
 .CodeMirror-vscrollbar, .CodeMirror-hscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-gutter-filler {
   position: absolute;
-  z-index: 6;
+  z-index: 7;
   display: none;
 }
 .CodeMirror-vscrollbar {