feature/add_xero___calendar_start_date_var

[fivetran-savage]

PR Overview

Package version introduced in this PR:

• 1.0.1

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

• GA-1006777

Summary of changes:

• adds xero__calendar_start_date variable to allow customers to specify earlier start dates than the calendar spine default.
• updates column name in vertical_general_ledger_tracking validation test to use tracking_option_name instead of the deprecated option column.

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

[fivetran-avinash]

@fivetran-savage Approved with one small comment. This shouldn't require a release review so it'll be ready to launch first thing Monday.