Added support to query all Product Variants in Product Projection Search in GraphQL

You can now fetch all Product Variants in productProjectionSearch queries in the GraphQL API. Previously, you had to use the masterVariant and variants separately to fetch all Product Variants.

Changes:

• [GraphQL API] Added the allVariants field to the ProductProjection type.

The following changes were introduced in terms of GraphQL SDL:

extend type ProductProjection {
  "Fetch all variants, including the master variant in first position."
  allVariants: [ProductSearchVariant!]!
}