DLCModelSource uses fetch1 when restricting by a secondary key

[CBroz1]

This portion of position_dlc_model

1. Uses a FreeTable to fetch a dependency
2. Presumes uniqueness of project_name that is not enforced by the DLCModelTraining table

spyglass/src/spyglass/position/v1/position_dlc_model.py

Lines 96 to 99 in a7b13fa

	table_query = dj.FreeTable(
	dj.conn(), full_table_name=part_table.parents()[-1]
	) & {"project_name": project_name}
	project_path = table_query.fetch1("project_path")

These should be removed in favor if restricting by the primary key of the parent, used directly