When the debug assets option is not activated, the assets are rendered with a space being trimmed from a string notation using backtick. This fix, uses the single quote notation to avoid this issue in `wysiwyg_iframe`. Without that fix, the structure of the dom is wrong and causes css rules to not be applied. task-3100202 X-original-commit: c54fcf21aecccac20b2c1d781132ed67df6c20a7 Part-of: odoo/odoo#112908