E2E: Write a separate test for accepting notifications

[LeandraH]

Is your feature request related to a problem? Please describe.
We currently check in e2e tests that the permission to send notifications is requested in each test because we don't know which one will be called first. If the permission request doesn't show up, an unrelated test fails, which isn't great. Additionally, with #2868, that check becomes optional, so we aren't testing the notifications at all anymore.

Describe the solution you'd like
I would like a new e2e test that does nothing other than open the app, wait for the permission popup to appear, and accepts it.

Describe alternatives you've considered
We could leave it untested but that's not great since we keep having problems with our notifications.