MAINT: Use add_bookmark_destination in add_bookmark_dict (#1099)

Re-use code

See #1098

PyPDF2/_writer.py

@@ -1055,7 +1055,7 @@ def getNamedDestRoot(self) -> ArrayObject: # pragma: no cover
  return self.get_named_dest_root()
 
  def add_bookmark_destination(
- self, dest: PageObject, parent: Optional[TreeObject] = None
+ self, dest: Union[PageObject, TreeObject], parent: Optional[TreeObject] = None
  ) -> IndirectObject:
  dest_ref = self._add_object(dest)
 
@@ -1096,18 +1096,7 @@ def add_bookmark_dict(
  action_ref = self._add_object(action)
  bookmark_obj[NameObject("/A")] = action_ref
 
- bookmark_ref = self._add_object(bookmark_obj)
-
- outline_ref = self.get_outline_root()
-
- if parent is None:
- parent = outline_ref
-
- parent = parent.get_object() # type: ignore
- assert parent is not None, "hint for mypy"
- parent.add_child(bookmark_ref, self)
-
- return bookmark_ref
+ return self.add_bookmark_destination(bookmark_obj, parent)
 
  def addBookmarkDict(
  self, bookmark: BookmarkTypes, parent: Optional[TreeObject] = None