feat: delete tlv2 creds with req_id matching item_id

[pavelbrm]

Summary

This PR builds on #2522, and updates the delete credentials endpoint to only delete TLV2 credentials that have a request id that matches the item id.

Type of Change

• [x] Product feature
• [ ] Bug fix
• [ ] Performance improvement
• [ ] Refactor
• [ ] Other

Tested Environments

• [ ] Development
• [ ] Staging
• [ ] Production

Before Requesting Review

• [x] Does your code build cleanly without any errors or warnings?
• [ ] Have you used auto closing keywords?
• [x] Have you added tests for new functionality?
• [ ] Have validated query efficiency for new database queries?
• [ ] Have documented new functionality in README or in comments?
• [ ] Have you squashed all intermediate commits?
• [x] Is there a clear title that explains what the PR does?
• [x] Have you used intuitive function, variable and other naming?
• [ ] Have you requested security and/or privacy review if needed
• [x] Have you performed a self review of this PR?

Manual Test Plan

[github-actions[bot]]

[puLL-Merge] - brave-intl/bat-go@2524

Description

This PR makes various changes to the SKUs service, including:

• Updates the CreateOrderCreds and createItemCreds handler functions to return more specific error responses
• Renames the DeleteOrderCreds handler to deleteOrderCreds and updates it to handle more specific error cases
• Adds an orderItemRepo dependency to the Service struct
• Updates the InitService function to take the new orderItemRepo dependency
• Adds getOrderFull and getOrderFullTx helper methods to retrieve an order with its items
• Deprecates some Datastore methods in favor of using the orderRepo and orderItemRepo directly
• Updates the DeleteOrderCreds service method to use a transaction and the new getOrderFullTx helper
• Adds a new DeleteLegacy method to the TLV2 repository for deleting legacy TLV2 order creds
• Updates tests

Changes

### Changes `services/grant/cmd/grant.go` - Updates call to `skus.InitService` to pass the new `skuOrderItemRepo` dependency `services/skus/controllers.go` - `CreateOrderCreds` and `createItemCreds` now return specific `404 Not Found` error if order is not found, `409 Conflict` if creds already exist, or `400 Bad Request` for other errors - `DeleteOrderCreds` renamed to unexported `deleteOrderCreds` - `deleteOrderCreds` updated to return specific errors - `499 Client Closed Request`, `404 Not Found` if order not found, `400 Bad Request` if order has no items or other errors - Minor formatting changes `services/skus/controllers_test.go` - Updates test setup to initialize the new `orderItemRepo` dependency - Minor test updates `services/skus/credentials.go` - `CreateOrderItemCredentials` now uses new `getOrderFull` helper to retrieve order with items - `DeleteOrderCreds` updated to use a transaction, new `getOrderFullTx` helper, and new `tlv2Repo.DeleteLegacy` method `services/skus/datastore.go` - `GetOrder` marked as deprecated in favor of `orderRepo.Get` or new `getOrderFull` helper - `DeleteTimeLimitedV2OrderCredsByOrderTx` marked as deprecated in favor of `tlv2Repo.DeleteLegacy` `services/skus/service.go` - Adds `orderItemRepo` field to `Service` struct - `InitService` updated to take `orderItemRepo` dependency - Adds `getOrderFull` and `getOrderFullTx` helper methods `services/skus/storage/repository/tlv2.go` - Adds new `DeleteLegacy` method for deleting legacy tlv2 order creds `services/skus/storage/repository/tlv2_test.go` - Adds test for new `DeleteLegacy` method

Security Hotspots

• The new deleteOrderCreds handler returns more detailed error messages, which could potentially leak sensitive information. The error messages should be reviewed to ensure they do not expose any internal system details.