Fixes issue in collection_remotes module where the requirements could not be blanked out

[Tompage1994]

What does this PR do?

Fixes issue where the [] which might be set against the requiremnets option is ignored.

How should this be tested?

Attempt to remove requirements from a remote as follows:

- name: Delete requirements
      infra.ah_configuration.collection_remote:
        name: test
        url: https://galaxy.ansible.com
        requirements: []

Is there a relevant Issue open for this?

resolves #413

Other Relevant info, PRs, etc

[djdanielsson]

LGTM