feat(oas): include /admin and /store in paths URLs (#3314)

## What

Include `/admin` and `/store` in OAS paths URLs

## Why

Allow for generating a combined OAS that include routes for both "admin" and "store" endpoint.

Fix potential issues with code generator where routes are not prefixed with "admin" and "store" leading to 404 errors.

## Test

* Run `yarn build`
* Run `yarn openapi:generate`
* Run `yarn redocly preview-docs docs/api/admin/openapi.yaml --config=./docs-util/redocly/config.yaml`
* Expect paths to be prefixed with /admin.
* Run `yarn redocly preview-docs docs/api/store/openapi.yaml --config=./docs-util/redocly/config.yaml`
* Expect paths to be prefixed with /store.

packages/medusa/oas/admin-spec3-base.yaml

@@ -292,7 +292,7 @@ tags:
   - name: User
     description: User endpoints that allow handling users in Medusa.
 servers:
-  - url: https://api.medusa-commerce.com/admin
+  - url: https://api.medusa-commerce.com
 paths: { }
 components:
   responses:

packages/medusa/oas/store-spec3-base.yaml

@@ -237,7 +237,7 @@ tags:
   - name: Swap
     description: Swap endpoints that allow handling swaps in Medusa.
 servers:
-  - url: https://api.medusa-commerce.com/store
+  - url: https://api.medusa-commerce.com
 paths: { }
 components:
   responses: