Add Invoice Notes to Subscription Create & Renew Flows

Problem Statement

Currently, there is no way to add invoice notes during the Subscription Create or Renew flows before an invoice is generated. As a result, invoices are created without the necessary context or details, requiring manual follow-up or adjustments after invoice generation.

User Story

As an admin,
I want to add invoice notes while creating or renewing a subscription,
So that the invoice is automatically generated with the correct notes included.