[MIRROR] Fixes an odd bug with record consoles (#26968)

* Fixes an odd bug with record consoles (#82103)

## About The Pull Request

1. Record computers never had ``character_preview_view`` set because it
was never returned, and it was additionally never deleted. This caused
an odd bug that, if you joined a round, ghosted, sent yourself back to
lobby, then rejoined, record consoles would no longer have a character
preview view. This fixes that, and also adds a define because I didn't
like the copypasta it had going on.

Security records currently have a big difference from the previous
version in that every person on the UI sees their own thing (it's local
instead of shared), which is a bigger problem that affects the whole
computer and really should be addressed.

This PR compliments https://github.com/tgstation/tgstation/pull/82105 -
This was a bug I found while working on that.

## Why It's Good For The Game

Fixes an odd bug with security records that I've been trying to find out
the cause to for a while.

## Changelog

🆑
fix: Clients joining a round twice as a crewmember (via admins or
otherwise) no longer break security/medical record consoles permanently.
/🆑

* Fixes an odd bug with record consoles

---------

Co-authored-by: John Willard <53777086+JohnFulpWillard@users.noreply.github.com>

code/__DEFINES/computers.dm

@@ -11,3 +11,6 @@
 #define CATEGORY_BEPIS "Bepis Tech"
 #define CATEGORY_BITRUNNING_FLAIR "Misc"
 #define CATEGORY_BITRUNNING_TECH "Tech"
+
+///Helper macro for record computers' preview views, used to ensure consistency in all use cases.
+#define USER_PREVIEW_ASSIGNED_VIEW(user_ckey) "preview_[user_ckey]_[REF(src)]_records"