Make the override settings of the Secure features more clear

The following discussion from !20449 (merged) should be addressed:

• @marcel.amirault started a discussion: (+1 comment)

  I think the example below is too similar to the new one you added. We should change this to be overriding something other than variables, like allow_failure or the stage, then it's a little clearer why we would do it this way, rather than the variables example above.

TL;DR: We use similar examples (variables), in customizing and overriding the CI templates. The overriding example should exemplify something else than variables.