Follow-up: Improve spec for "security training promo to MR widget"

The following discussion from !99547 (merged) should be addressed:

• @dpisek started a discussion: (+1 comment)

  suggestion (non-blocking): I feel like getting elements by index (and therefor their DOM-order) is always a bit fragile. Maybe we could use a testid instead? 🤔

  But happy to leave as-is too, since it's not likely that we'll be adding to this component anyways 👍