Pull request checklist

• Addresses an existing issue: Fixes Dropdown errorMessage style inconsistent with TextField errorMessage style #3748
• Include a change request file using $ npm run change

Description of changes

• Error message text styling now aligns with TextField's
• New example for documentation so we can see this functionality
• Fixed border color states when there is an error
• Also fixed border color states for ComboBox and TextField to be consistent, not all states were red, they should be
• Tweaked some example scss to match patterns we're using with other examples

Focus areas to test

(optional)