VSA: Stage ID mismatch in specs

It appears that the JSON fixtures we are using in our VSA mock data generate stages with numeric IDs. However, we are using alphabetic stage ids in our specs.

This causes issues when we are doing lookups, like in transformStagesForPathNavigation as this won't return any findings.

As a result, stage data in our specs doesn't have metrics but undefined instead.

• We should ensure we update related specs, such as !59606 (comment 556254202)