Web eID dialog disposing

TODO: Add a diagram that depicts the call and event chains that cause the Web eID dialog to be disposed and deleted.

There are a number of different scenarios that cause the disposal:

1. retriable error occurs, user clicks Retry,
2. fatal error occurs,
3. user clicks Cancel on the dialog,
4. user clicks OK on the dialog,
5. user clicks Cancel on the PIN pad,
6. user clicks OK on the PIN pad.