"Down" arrow should be changed to "Up" arrow when the logout modal is shown

Reproduction Steps

1. login to the app, click the down arrow on top right

Expected Result

"Down" arrow should be changed to "Up" arrow when the logout modal is shown.

Actual Result

See screenshot

Screenshot and/or screencast

Issue Information

Device/OS: Mac Book Pro, macOS Catalina Version 10.15.5

Browser Version: Firefox 78.0.2 (64-bit)

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/u-bahn-app/issues/65