Less restrictive snapshot test for recipes

[EmilHvitfeldt]

When I prepped the {recipes} release, I ended up temporarily undoing a change in an warning, because it would have otherwise stopped the release. If would be nice if we could make the hardhat test a little less fragile

tidymodels/recipes@55da6dc

corresponding {hardhat} test

hardhat/tests/testthat/test-forge-recipe.R

Lines 163 to 169 in ac2dfd0

	expect_warning(
	expect_warning(
	xx2 <- forge(new, x2$blueprint),
	"Novel levels found in column 'f': 'e'"
	),
	"There are new levels in a factor: NA"
	)

[DavisVaughan]

i think we should make them actual snapshot tests, rather than expect_warning() calls