[hooks] fix extra_props handling on python3
The json module expects str, not bytes, so we need to do the decoding.
sync_schema_props_perms('state_of')
sync_schema_props_perms('transition_of')
sync_schema_props_perms('State')
sync_schema_props_perms('BaseTransition')
sync_schema_props_perms('Transition')
sync_schema_props_perms('WorkflowTransition')