Indent fixed in "choices__list--dropdown"

[dmitrach]

Indent fixed in "choices__list--dropdown". Added "box-sizing: border-box;".

Description

Interconnected with #749

Screenshots (if appropriate)

Before: https://yadi.sk/i/DUrKF9Nlet1WsA
After: https://yadi.sk/i/w_x6W8pBhTBRpA

This is with fix #749

Types of changes

• Chore (tooling change or documentation change)
• Refactor (non-breaking change which maintains existing functionality)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[jshjohnson]

Thanks 👍