All users should be available for inspection in audit events

Overview

According to @kyletsmith in #32388 (comment 224078059):

When filtering by User Events only active users appear to be available in the user picker filter. This prevents researching actions taken by or on blocked accounts which is an additional limitation of the current feature.

All users on the instance should be available.

Proposal

Include all users (including blocked and bot users) in the user filter when inspecting User Events in the Audit Events view.