Requests query excludes requests no longer owned by a user

Checklist

• I confirm that this is an issue with aurweb's code and not a user-uploaded package.
• I have described the bug in complete detail in the Description section.
• I have specified steps in the Reproduction section.
• I have included the versions which are affected in the Version(s) section.

Description

When viewing package requests as an elevated user (a TU or above), package requests which do not have a valid User association are excluded from the list. This can occur when a user previously files a package request, then their account is deleted in some way.

Package requests which have been filed should remain valid until dealt with.

Reported by @artafinde

Reproduction

1. As a normal user, file a package request
2. Login as a TU, view Requests, where you can see the package request which was just created
3. Delete the account manually: DELETE FROM Users WHERE Users.Username == '<the_normal_users_name>';
4. Login as a TU, view requests, where you can no longer see the package request which was just created.

Version(s)

v6.1.2