[Backport] Set proper text-aligh for the <th> element of the Subtotal column in the Creditmemo email

[TomashKhamlai]

Description

#17153

Fixed Issues (if relevant)

1. We definitely do not need this

Manual testing scenarios

1. Create an Invoice
2. Create a Credit Memo
3. Check the email that was sent to the Customer

Expected result:

Actual result:

The Luma and the Blank theme are affected

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-cicd2]

All committers have signed the CLA.

[magento-engcom-team]

Hi @TomashKhamlai. Thank you for your contribution.
We will aim to release these changes as part of 2.1.15.
Please check the release notes for final confirmation.