Bug Report

• Package version(s): office-ui-fabric-react 1.14.2
• Browser and OS versions: EDGE, Windows 10

Priorities and help requested (not applicable if asking question):

Are you willing to submit a PR to fix? (Yes, No)
No
Requested priority: (Blocking, High, Normal, Low)
Normal

Describe the issue:

When in high contrast mode, Dropdown list focused item is black and not visible.

Actual behavior:

When in high contrast mode, Dropdown list focused item is black and not visible.

Expected behavior:

When in high contrast mode, Dropdown list focused item background color and font color should be such that they are visible.

If applicable, please provide a codepen repro: