Re-add checking on previous release of R.

[ddsjoberg]

we just added a Suggested dependency on emmeans, which depends on estimability. The latter package now requires R >= 4.3.0 so the checks on the previous release are failing. I've commented out the checks for now. But we can add it back after the next release, which is scheduled for later this month

# - {os: ubuntu-latest, r: 'oldrel-1'}

[ddsjoberg]

added in #165