(Clean Ibexa Experience v4.2.0)

Steps to reproduce:

• Add tags to taxonomy tree:
  
• after this operation there will be 3 new entries in ezcontentobject and ezcontentobject_tree tables (one for each tag) 
• Remove Tag1

Result:

• row for Tag1 is removed from ezcontentobject and ezcontentobject_tree tables
• rows for Tag2 and Tag3 are still present in ezcontentobject and ezcontentobject_tree tables

Expected result:

• all rows for Tag1, Tag2 and Tag3 should have been removed