erp5_web_renderjs_ui: fixup invalid class selector

See ea219b74
4 jobs for cmf_upgrade_versions in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.UnitTest-Master

02:08:27

passed SlapOS.Eggs.UnitTest-Master.Python2

00:40:34

passed SlapOS.Eggs.UnitTest-Master.Python3

00:09:30

failed ERP5.UnitTest-Master