Resolve discrepancy in trial ending dates for extended trials

What does this MR do and why?

Use the same database value for displaying trial end date on the billing page.

How to set up and validate locally

Bug in original issue is not reproducible since code here ensures two end dates are the same.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #300699