Comment 1 for bug 1932144

But it is trivial to offer those that are configured/enabled for the snap.

So just offer the choice of `snap.processors_collection_link`.

I.e. i configure the snap for arm64 s390x. and then request-builds page should offer me tickboxes to build selectively for either arm64 or s390x or both.

Even when series is inferred from snapcraft.yaml.