fix(medcat-trainer): CU-869c1h5qh Model pack saving error fix by updating kwargs

[alhendrickson]

Error before on model pack save, including using the new Admin form.

[medcattrainer] File "/home/api/api/models.py", line 140, in save  
[medcattrainer] super().save(*args, update_fields=['concept_db', 'vocab'], **kwargs)
[medcattrainer] File "/usr/local/lib/python3.11/site-packages/django/db/models/base.py", line 852, in save 
[medcattrainer] raise ValueError("Cannot force both insert and updating in model saving.")
[medcattrainer] ValueError: Cannot force both insert and updating in model saving.

Fix

Remove force_insert and change to force_update from the kwargs

[medcattrainer] INFO 2026-02-10 14:55:08,117 models.py l:148:ModelPack.save() - Before modification: kwargs={'force_insert': True, 'using': 'default'}, pk=1, _state.adding=False
[medcattrainer] INFO 2026-02-10 14:55:08,117 models.py l:152:ModelPack.save() - Removed force_insert=True from kwargs
[medcattrainer] INFO 2026-02-10 14:55:08,117 models.py l:154:ModelPack.save() - After modification: kwargs={'using': 'default', 'force_update': True}, update_fields=[concept_db, vocab]

[tomolopolis]

Task linked: CU-869c1h5qh Fix load examples - Remove kwargs from modelpack.save as they error

[mart-r]

Looks like a reasonable fix to me