Dismiss toasts instead of waiting for them to disappear

[asnaith]

Update the tests so that we close the "upload complete" / "delete successfully" toasts instead of waiting for them to disappear, this should speed up overall test time.

Acceptance criteria:

• Unique identifier is added for the upload toast displaying "upload complete" (at the moment all upload-related toasts share the same identifier).

• Add an identifier to the toast close button that appears when hovering over it

• Update all test steps where we are waiting for toasts to disappear. Replace them with an action to dismiss the toast instead