Issue with Linked KItems before dsms.commit

[MBueschelberger]

In this case, we are considering a workflow without commiting (yet).

After the validation, a linked kitem is referenced as LinkedKItem object when appending to the linked_kitem property of a KItem object (seems legit).

item.linked_kitems = [another_item]
assert isinstance(item.linked_kitems[0], LinkedKItem)

When another kitem is appended in afterwards, the latest implementation fails:

item.linked_kitems += [yet_another_item]

Traceback:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "C:\Users\BUE\al-alloy-aging-use-case\al_alloy_aging\integrate.py", line 251, in <module>
    integrate()
  File "C:\Users\BUE\al-alloy-aging-use-case\al_alloy_aging\integrate.py", line 229, in integrate
    treatment.linked_kitems = [before_specimen_kitem, after_specimen_kitem] + [linked for linked in treatment.linked_kitems]
    ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Anaconda3\envs\sdk\Lib\site-packages\dsms\knowledge\kitem.py", line 230, in __setattr__
    super().__setattr__(name, value)
  File "C:\Anaconda3\envs\sdk\Lib\site-packages\pydantic\main.py", line 817, in __setattr__
    self.__pydantic_validator__.validate_assignment(self, name, value)
pydantic_core._pydantic_core.ValidationError: 1 validation error for KItem
linked_kitems
  Value error, KItem with uuid `3799baf3-ff56-4dab-b8a5-eeed3f6dfe4f` does not exist in
            DSMS-instance `https://bue.materials-data.space/` [type=value_error, input_value=[KItem(

        name = Specimen...
                        updated_at: None
                ], input_type=list]
    For further information visit https://errors.pydantic.dev/2.7/v/value_error

This is because a linked kitem is not commited to the backend yet and the validator tries to download it.

A better solution would be to add a lookup from the buffers before trying to download from the remote backend.