Add/disabled option in dropdown

[mustran]

OVERVIEW

Add disabled option for dropdown options.

WHERE SHOULD THE REVIEWER START?

e.g. /src/elements/SomeComponent.js

HOW CAN THIS BE MANUALLY TESTED?

List steps to test this locally.

ANY NEW DEPENDENCIES ADDED?

List any new dependencies added.

• Does it work in IE >= 11?
• Does it work in other browsers?

SCREENSHOTS (if applicable)

Does your change affect the UI? If so, please add a screenshot.

CHECKLIST

Be sure all items are ✅ before submitting a PR for review.

• Verify the linters and tests pass: yarn review
• Verify you bumped the lib version according to Semantic Versioning Standards
• Verify you updated the CHANGELOG
• Verify this branch is rebased with the latest master

[Jasminna]

LGTM