As suggested in #49043, this PR will adjust the messaging when deleting a Domain Mapping subscription in order to better communicate the ramifications of removing it.
Testing instructions
Add a domain mapping to any plan.
Navigate through Upgrades > Domains > click on the domain mapping.
Click Delete Domain Mapping at the bottom.
You should be presented with a modal showing an updated message:
Are you sure you want to remove DOMAIN from SITEADDRESS? You will not be able to reuse DOMAIN again without starting a new Domain Mapping subscription.