Fix front press order

#5921 completely broke the order of `FrontPress`ing by the arbitrary use of a `Map`.

It was then never tested on any of the environments, left in a broken state on `CODE` AND left undeployed to `PROD` all weekend.

This changes back to something that actually guarantees sequence. Before it was `Iterable` coming from a `List`, but now we are being more explicit by the use of `Seq`.

As discussed, we are probably going to need tests for this part of the code, as it is the heart of our fronts and if it went to `PROD` could have been quite bad.

@robertberry @tudorraul