Feature Request: Prefer custom distinct IDs to UUIDs in person IDs dropdown

Feature request

Is your feature request related to a problem?

On the persons page we show a dropdown of all distinct_ids assigned to a person. It would be better UX if we displayed any 'custom' distinct_ids there by default in preference to anonymous ID(s) assigned to that person - on the basis of it not being a UUID. In the example below, we should always display user_ ahead of the UUID.

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/40865 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/42778)

Debug info

Kind: support

Target area: analytics

Report event: http://go/ticketByUUID/948b9b85-3a5f-4fcf-b9bb-f98a60bd95fc

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/019a14f6-f591-7712-abaa-b7600e27749c?t=1193

Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%22019a14f6-f591-7712-abaa-b7600e27749c%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://eu.posthog.com/project/80143/persons/70238cdf-0533-5a7c-a29a-d2e2be7778af

Persons-on-events mode for project: person_id_override_properties_on_events

Start at the persons page entry point and locate the distinct_id dropdown implementation. Trace how IDs are classified and ordered, then verify that a custom non-UUID ID appears before anonymous UUIDs in the rendered dropdown, covering the behavior with the relevant existing test.