make referenced_filenames required phrases

## Short Description

It seems that the `referenced_filenames` are ignored by the license scan, while these should be required phrases.

## Possible Labels

- new feature

## Select Category

- [X] Enhancement
- [ ] Add License/Copyright
- [ ] Scan Feature
- [ ] Packaging
- [ ] Documentation
- [ ] Expand Support
- [ ] Other

## **Describe the Update**

Currently `referenced_filenames` from .RULE files seem to be ignored by the license scanner, while these should be required phrases. An example of a rule where this is going wrong is #4949.

## **How This Feature will help you/your organization**

It would mean fewer false positives

## **Possible Solution/Implementation Details**

Treat `referenced_filenames` as required phrases.

## **Example/Links if Any**

## **Can you help with this Feature**