Steps to Reproduce:

1. On the clusters list page, click on a ready OSD cluster
2. Navigate to the Add-ons tab and click on the addon for which there is no quota or does not fulfill prereqs.
3. Provide the details and click on the Install button.
4. An error message is shown to the user. 
5. Observe the layout of the error message.

Expected Result:
There should be an "X" button to dismiss/cancel the alert.
Clicking on the refresh button makes the alert disappear.

Actual Result:
There is no "X" button to cancel/dismiss the alert.
Clicking on the refresh button does not make the alert disappear. The user has to refresh the browser at the top of the page to dismiss the alert manually.