Make packages/medusa/src/services/inventory.js pass linting #509

Editor assessment

The subject states the mechanical task completely — packages/medusa/src/services/inventory.js made to pass linting — with chore correctly classifying the work, and the trailing '#509' reference riding along. No body records which rules were offended or how they were satisfied, which is acceptable at this scale but leaves the message purely mechanical. Accurate, appropriately typed, and finished in one clause: it communicates the fact of a lint cleanup and nothing beyond it.