Update dashboard tests to clearAllToasts

[liza-mae]

This issue is related to #20008 since we don't want to call the JS click button directly, which is a valid workaround to the selenium error and since I only see the issue on dashboard tests, @stacey-gammon recommends using clearAllToasts() method. Will look into putting this as a fix.

[liza-mae]

I am still in favor of the fix: #20045 since it won't block the dashboard tests in the case notifications are broken. Notifications though should also have their own functional tests.