Setting the parent of a document in using the breadcrumb by the document itself crash the page with error Nb 4001

Bug description
Setting the parent of a document in using the breadcrumb by the document itself crash the page with error Nb 4001.

Step to reproduce :

• Create a new page
• Save the page
• Change the parent of the page by using the page itself
• Save the document

Expected result :

• In edit mode : Page not present in the suggest
• In edit mode : If page name is forced, a validation message saying that this page name can't be picked since it's the actual name. Then clean the field
• If the imported page has the issue; check on import or check on display and prevent the page to crash in displaying an error for admins instead of the breadcrumb.
• We could also reset the parent to the Homepage page set in preference

Workaround

• I exported as a XAR an other page and modified it in the xml to replace the failing document in importing it after the modification.