core: fix edit_workflow/edit permission

This transition should not be more restrictive that the original
method ie. 'Modify portal content' for "real" documents and public
for temp objects.
8 jobs for feat/bt-script-magic
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

passed ERP5.PerformanceTest-Master

00:27:08

failed ERP5.UnitTest-Master

failed ERP5.UnitTest-Master.Medusa

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:11

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:24

passed SlapOS.Eggs.UnitTest-Master.Python2

passed SlapOS.Eggs.UnitTest-Master.Python3