Add includeInactive argument to inventoryLevels and inventoryLevel fields

Shopify's Admin GraphQL API version 2026-04 adds an optional `includeInactive` boolean argument to the `inventoryLevels` and `inventoryLevel` fields on `InventoryItem` and `Location` objects. Previously, inactive inventory levels could not be retrieved via the API. The new argument defaults to `false`, so existing queries are unaffected. Apps that need to access inactive inventory levels must explicitly pass the argument in their queries.