test: added tests for the cmd-filters package

[VaibhavMalik4187]

📑 Description

This commit adds new tests for the cmd/filters package. As a result, the code coverage of the package has increased from 0% to almost 75%

This also includes a minor adjustment in the list command. Now, the list of the filters will always be in sorted order for better consistency.

✅ Checks

• [x] My pull request adheres to the code style of this project
• [ ] My code requires changes to the documentation
• [ ] I have updated the documentation as required
• [x] All the tests have passed

[VaibhavMalik4187]

@AlexsJones, I've tried to add some tests to the cmd-filters package and a minor modification in the filters list command. Could you please go through this PR whenever you have a moment? Thanks!

[VaibhavMalik4187]

@AlexsJones, I've fixed the CI errors.