SAC-31563 Updated Schemas

[rsaha-qlik]

Description of change

https://qlik-dev.atlassian.net/browse/SAC-31565

⚠️ Breaking Changes

This PR includes schema changes that may require downstream updates and is released as v2.0.0.

What changed

• products.custom_fields is now strictly typed as ["array", "null"] with object items (name, value, id).
• Several previously non-nullable container fields were updated to allow null to match API behavior:
  • products.categories
  • products.related_products
  • coupons.applies_to
  • orders.billing_address
  • products.bulk_pricing_rules

Why this is breaking

• Pipelines that assumed a different shape for products.custom_fields (for example, object/non-array handling) may fail validation or transformation after upgrade.
• Strict schema-based loaders/models may need updates to reflect these type constraints.

Action required

• Review downstream models/transformations for products.custom_fields and ensure they handle only array-or-null.
• Confirm warehouse/table definitions and dbt models accept nullable values for the updated fields above.
• Re-run discovery and refresh catalog/schema artifacts before next sync.

Manual QA steps

Risks

Rollback steps

• revert this branch

AI generated code

https://internal.qlik.dev/general/ways-of-working/code-reviews/#guidelines-for-ai-generated-code

• this PR has been written with the help of GitHub Copilot or another generative AI tool

[Copilot]

Pull request overview

Updates Singer JSON schemas for the BigCommerce tap to better reflect nullable API fields and fix downstream loading issues with target-snowflake (per SAC-31565).

Changes:

• Allow null for several array-typed fields in products (e.g., categories, related_products, bulk_pricing_rules).
• Correct products.custom_fields to be a nullable array of objects (instead of an object).
• Allow null for nested objects that can be absent/empty in payloads (orders.billing_address, coupons.applies_to).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
tap_bigcommerce/schemas/products.json	Makes selected arrays nullable and fixes custom_fields to a nullable array of objects.
tap_bigcommerce/schemas/orders.json	Allows billing_address to be null while keeping the object shape.
tap_bigcommerce/schemas/coupons.json	Allows applies_to to be null while keeping the object shape.

[rsaha-qlik]

Updated this wrt the doc: https://docs.bigcommerce.com/developer/api-reference/rest/admin/catalog/products/get-products