Motivation:

In some tests (karate), apparently the operating user is non-existing. It may exist - but not for the tenant where the operation is performed. The check for the operating user fails and the permission assignment fails with the code introduced in MODPERMS-157.

Procedure:

Do not fail if operating user does not exist.. Instead in this case, assume the operating user has no permissions (empty set). The sole requirement is instead the the module permissions (modulePermissions in routing entry) has what it takes. This allows modules to create user with any permissions they want, but those must be listed in one of two ways:

1. the modulePermissions include perms.users.assign.immutable ..

2. the modulePermissions include the permissions that are assigned for the user to be created.

The 2nd approach is better as it clearly states what the module user will end up having .. With number 1, the module user may get any immutable permission (or at least the permissions must be checked somewhere else).