Add allow duplicates option to M2A and M2M interfaces

Description

Implements #14938

Adds a new field Allow duplicates to M2M and M2A interfaces that disables filtering of lists when adding existing items.

Type of Change

• [ ] Bugfix
• [x] Improvement
• [ ] New Feature
• [ ] Refactor / codestyle updates
• [ ] Other, please describe:

Requirements Checklist

• [ ] New / updated tests are included
• [ ] All tests are passing locally
• [ ] Performed a self-review of the submitted code

If adding a new feature:

• [ ] Documentation was added/updated