check.bety.version() errors instead of warning about unknown database migrations #4165

check.bety.version() (base/settings/R/check.all.settings.R) calls any(unknown_migrations) on a character vector. When the database has a migration this release doesn’t know, R warns about coercing character to logical, then if (NA) fails with “missing value where TRUE/FALSE needed”. The intended warning never appears. Fix: test length(unknown_migrations) > 0. Reproduce by mocking db.query to return the known versions plus one extra.

I have a PR with tests: #4155.