Notification clear control is invisible

[AlbyIanna]

The X that is normally shown at the top right corner of the notification is invisible. This means there is no obvious way to dismiss notifications

Steps to reproduce

1. Generate a notification, which can be done by selecting a board from a platform that was not yet installed. Note that there is no X at the top right corner. If you hover the mouse over the corner you can see the "Clear" tooltip and clicking that location does close the notification.

Expected behavior

A visible control is shown for dismissing a notification.

Environment

Version: 2.0.0-beta.11-snapshot.da6b66f
Date: 2021-10-06T08:06:21.909Z
CLI Version: 0.19.1 alpha [718bbbf2]
OS: Windows 10

Additional information

The issue does not occur when using 2.0.0-beta.11