Resolves Issue #1901, #1902, #1903: Fix registry auth repository fallback paths

[afoote-mitre]

Closes Issue #1901, #1902, #1903

Summary

Fixes three repository/auth-context issues that prevented some registry and legacy compatibility paths from working correctly, and updates unit test fixtures to reflect requester UUID lookup behavior.

Important Changes

src/repositories/userRepository.js

• Fixed getUserUUID() to pass options as the fourth argument to utils.getUserUUID().

src/utils/authContext.js

• Updated method detection so ES6 class prototype methods are recognized correctly.

src/repositories/baseOrgRepository.js

• Fixed legacy selected short-name lookup to instantiate OrgRepository before calling instance methods.

test/unit-tests/*

• Added and updated unit coverage for user UUID forwarding, auth context prototype method detection, legacy org lookup, and CVE rejection requester lookup.

Testing

Steps to manually test updated functionality, if possible

• 1. Run bash -i -c "npm run test:unit-test".
• 2. Verify registry org GET tests pass for regular users and org admins requesting expand=users.
• 3. Verify CVE rejection tests pass for both Secretariat and regular requester paths.