[Forwardport] FR#7428 - Multiline fields in forms have no visible label

[rostyslav-hymon]

Original Pull Request

#14317
Change css to label multifields

Description

admin__field-label has opacity 0, change to 1

Fixed Issues (if relevant)

1. Multiline fields in forms have no visible label #7428: Multiline fields in forms have no visible label

Manual testing scenarios

1. Create a
2. Set it's formElement to multiline
3. Load the form in the browser

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)