Rename staging models to align with new source tables

[fivetran-jamie]

Following the release of v1.3.1, during our next breaking change we should rename the following staging models to align with the most up-to-date connector table names:

• stg_shopify_gql__order_note_attribute -> stg_shopify_gql__order_custom_attribute
• stg_shopify_gql__tax_line -> stg_shopify_gql__order_line_tax_line
• stg_shopify_gql__order_line_refund -> stg_shopify_gql__refund_line_item