"Enroll existing user" as reviewer no longer finds users outside the current journal

[asmecher]

Describe the bug
As an Editor, when attempting to enroll an existing user as a reviewer, it's no longer possible to find users who are not active in the current journal. This used to be possible in OJS 3.3.0-x.

To Reproduce
Steps to reproduce the behavior, starting from the test dataset:

1. As an administrator, create a second journal
2. Register a new account in the second journal as a reviewer
3. Log into Journal Manager in the Journal of Public Knowledge (first journal)
4. Go to the review workflow for a submission
5. Click "Add Reviewer"
6. Click "Enroll existing user"
7. Attempt to search for the new account; it will not be findable.

What application are you using?
OJS 3.4.0

Additional information
Please add any screenshots, logs or other information we can use to investigate this bug report.

[asmecher]

PRs:

• pkp-lib stable-3_4_0: pkp/pkp-lib#10373 Fix enroll existing user as reviewer feature #10374
• ojs stable-3_4_0 (tests only): pkp/pkp-lib#10373 Fix enroll existing user as reviewer (Tests only) ojs#4429

(Needs forward-porting to main after review)

[asmecher]

@defstat, could you review the PR above?