## What
Fix typing on ShippingOptionService.list selector parameter
## Why
A backend server interfacing with the `ShippingOptionService.list()` method will throw TS error when attempting to pass selector values that should be valid.
## Steps to reproduce
* In a IDE that can display TS errors
* Create an instance of the ShippingOptionService
* Call the `list()` method on the instance with the following selector parameter: `{ region_id: "foobar" }`
* Expect: No TS error
* Actual: `TS2345: Argument of type '{ region_id: string; }' is not assignable to parameter of type 'Selector<ShippingMethod>'.`
## How
* Change the `selector` type to `Selector<ShippingOption>`
* fix(search): add missing default product relations
Add missing default product relations for events calling SearchService.addDocuments
For the following events: `ProductService.Events.UPDATED, ProductVariantService.Events.CREATED, ProductVariantService.Events.UPDATED]`,
`SearchService.addDocuments` will fail due to `product` missing its `variants` relations.
The issue can be observed with the Algolia plugin where `reduce` is being attempted on `product.variants`.
https://github.com/medusajs/medusa/blob/develop/packages/medusa-plugin-algolia/src/utils/transformer.ts#L14
Implement the same retrieve pattern as `handleProductCreation` method.
* chore(changeset): patch
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Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>
patpich
