Fix vocabulary binding validation on rename

Steps to reproduce:

• Drag and drop a schema property in a layout (document creation / view / update layouts, form layout or table layout) and use a vocabulary widget (e.g. single or multiple directory suggestion)
• Associate to it a custom vocabulary created in Studio
• Rename that vocabulary

=> The reference is not updated in the layout,
=> Studio does not flag with a red badge that there is an invalid reference to a non-existing vocabulary
=> The error is encountered at runtime when the binding done and the single-vocabulary-suggestion fails to find the vocab.

This is a regression as this validation was done in the past.