feature/add_invoice_variables

[fivetran-savage]

PR Overview

Package version introduced in this PR:

• 1.4.1

This PR addresses the following Issue/Feature(s):

• GA-1030924

Summary of changes:

• Adds the xero__using_invoice and xero__using_invoice_line_item variables (both default true) so you can run the package without invoice or invoice_line_item data.

Submission Checklist

• Alignment meeting with the reviewer (if needed)
  • Timeline and validation requirements discussed
• Provide validation details:
  • Validation Steps: Check for unintentional effects (e.g., add/run consistency & integrity tests)
  • Testing Instructions: Confirm the change addresses the issue(s)
  • Focus Areas: Complex logic or queries that need extra attention
• Merge any relevant open PRs into this PR

Changelog

• Draft changelog for PR
• Final changelog for release review