Language cleanup on mass actions from the Customers grid

[p-maguire]

Description (*)

This pull request corrects a few grammar issues on the "Delete" and "Customer Unsubscribe from Newsletter" mass actions on the Customers grid.

Fixed Issues (if relevant)

1. None

Manual testing scenarios (*)

1. Login to admin and go to Customers-->All Customers
2. Select one or more customers
3. Select the "Delete" or "Unsubscribe from Newsletter" options.

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 @p-maguire. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento-engcom-team give me test instance - deploy test instance based on PR changes
• @magento-engcom-team give me $VERSION instance - deploy vanilla Magento instance

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[magento-engcom-team]

Hi @sidolov, thank you for the review.
ENGCOM-3249 has been created to process this Pull Request

[magento-engcom-team]

@p-maguire thank you for contributing. Please accept Community Contributors team invitation here to gain extended permissions for this repository.

[magento-engcom-team]

Hi @p-maguire. Thank you for your contribution.
We will aim to release these changes as part of 2.3.1.
Please check the release notes for final confirmation.