Simply "Select To Field" selection

Problem/Motivation

When you go to choose the "Copy To" field (case 2), you are shown all applicable fields, however, you're also shown the field that you chose as "Copy From."

Proposed resolution

Looking at the UX, maybe there is an opportunity to remove that "Copy From" field from the list and keeping it simpler for users.

Remaining tasks

1. Get thoughts from maintainers
2. Create patch for changes in BulkCopyFieldsForm.php

User interface changes

Select dropdown has one less field.

API changes

N/A

Data model changes

N/A