[FIX] web_editor: ace have line number+resize

After 11.0, in a code editor (ace editor) on the frontend we could not
resize the editor or see line numbers.

This happen since:

- in 64d47c0bc5 ace editor (used when editing code) was updated.
- in ajaxorg/ace@5bf78e09 the line number bar was set aria-hidden
- in 9de1bc0ee aria-hidden element were forcibly hidden

Thus the column of line number (and used for resizeing) in the code
editor was unwillingly hidden.

Since we don't want to make change in library, we fix this in our
custom CSS for the code editor.

opw-1912824
closes #29399

addons/web_editor/static/src/scss/web_editor.ui.scss

@@ -1239,6 +1239,7 @@ body.editor_enable {
         height: 70%; // in case flex is not supported
         flex: 1 1 auto;
         .ace_gutter {
+            display: block!important; // display even with aria-hidden
             cursor: ew-resize;
 
             .ace_gutter-cell.o_error {