The endpoint loaded the full merged YAML+DB config and re-saved every
top-level section to LiteLLM_Config rows via save_config(), so a UI toggle
of one field persisted unrelated YAML state to DB as a side effect. It
also rejected every request when store_model_in_db was False — including
the request that would flip the flag to True (chicken-and-egg).
Replace save_config with targeted per-section upserts: read the existing
litellm_config row, merge in the request, upsert just that row. Sections
the caller did not send are not touched. Drop the blanket
store_model_in_db guard — the endpoint already requires prisma_client,
and the startup-side override at proxy_server.py:6491 picks up
general_settings.store_model_in_db=True from the DB on next restart.