Add validation of examples

[olantwin]

We should probably validate that the examples run for each change to them (in this repo), and maybe run them in the phlex CI to make sure we know when they need updating?

Do the examples target the latest release or phlex main?

[knoepfel]

@olantwin, agreed—we need to validate the examples. @greenc-FNAL is currently reorganizing our GitHub actions. Once that has stabilized, we should incorporate this repository in some way into the CI test system.