Extend GlExperimentBadge to work for Beta as well

At the moment, the component works only for the Experiment features. The issue suggests to extend it to work with Beta as well.

• The copy for the supporting text can be found in https://design.gitlab.com/usability/feature-management#highlighting-feature-versions
• The link to "Beta" documentation: https://docs.gitlab.com/ee/policy/experiment-beta-support.html#beta