If an event participant's account is blocked+suppressed, they won't appear on Special:EventDetails. This makes the "X participants" label inconsistent with what is actually shown, and can result in equally confusing behaviour when selecting/searching/removing participants. As an example, see item (2.) in the description of T320649. Also, suppressed participants cannot be removed unless you choose to remove all participants. These inconsistencies also makes it harder to maintain the relevant code.
As such, I propose that deleted/suppressed participants be shown on EventDetails. Visually, entries for deleted users would be identical to those for visible users, but there would be some text saying "username suppressed" (or similar, consistently with what we do for organizers) instead of the username. It goes without saying that no suppressed users should be shown when searching by username.
Acceptance criteria
Assuming that an event has participants whose accounts were either deleted or suppressed, if I am on Special:EventDetails for that event, then:
- Deleted participants are listed, and there's grey text saying "deleted user" instead of the user page link
- Suppressed participants are listed, and there's grey text saying "username suppressed" instead of the user page link
- If I scroll down until all participants are loaded, the number of participants shown in the interface should match the number at the top of the panel ("X participants")
- The label which reads "X selected" will also have the correct number of participants; that is, problem (2.) described in T320649 should be fixed
- The documentation of the "List the participants of an event" endpoint is updated and it includes the new properties added to the response.
