Remove dependency on "acquisition method" interface as it no longer exists

the package.json file's list of okapi dependencies includes

"acquisitions_method": "1.0"

Please remove this as mod-orders-storage no longer implements that API. Acquisition method is now defined as an enumeration the acq-model schemas.

see https://github.com/folio-org/acq-models/blob/8f5e69639789eea400f7f0fd86e80f5d0c53965e/composite_po_line.json#L11