Don't include prerelease probe in release histories

[georgf]

trafficstars

Currently we include all probes for the release channel data, even when they are only ever recorded on prerelease.

It probably makes more sense to just not include prerelease probe data for release.

@Dexterp37 @fbertsch Thoughts?

[Dexterp37]

Given the recent changes to the Preferences on the client side, I think your proposal makes sense. Moreover, if we want all the probes for all the channels we can simply query the firefox/all/main/all_probes instead of firefox/release/main/all_probes.

The only caveat I can think of (not a problem for now): what if other, future, products will diverge from our current notion of release/prerelease data?

[fbertsch]

Big +1 from me on this. It aligns with the notion of pre-release and release well.