Feature Request: Customized Donation Block Receipt

### Impacted plugin

Jetpack

### What

Add a personal brand and customized message to the Donation Block receipt

### How

It would very useful to be able to create a customized, branded receipt that gets emailed to donors upon transactions via the Donation block.

This could be a custom thank you message that might include something like an organization’s 501(c)(3) nonprofit status.

Possible Areas to customize:

Where the customization could be located:

No files, tests, or entry points are named. Start by locating Jetpack's Donation Block receipt and email flow, then determine how receipt branding and custom messages should be configured. Done means donors receive a transaction receipt containing the organization's requested branding and message.

Written by the indexing model from the issue text.