refactor(config): Explicit asserts instead of lonely snapshots (#11174)

lib/config/__snapshots__/massage.spec.ts.snap

lib/config/__snapshots__/migrate-validate.spec.ts.snap

lib/config/__snapshots__/migration.spec.ts.snap

lib/config/massage.spec.ts

lib/config/migrate-validate.spec.ts

lib/config/migration.spec.ts

lib/config/presets/__snapshots__/index.spec.ts.snap

...presets/bitbucket-server/__snapshots__/index.spec.ts.snap

lib/config/presets/bitbucket-server/index.spec.ts

lib/config/presets/gitea/__snapshots__/index.spec.ts.snap

lib/config/presets/gitea/index.spec.ts

lib/config/presets/github/__snapshots__/index.spec.ts.snap

lib/config/presets/github/index.spec.ts

lib/config/presets/index.spec.ts

lib/config/presets/local/__snapshots__/index.spec.ts.snap

lib/config/presets/local/index.spec.ts

lib/config/presets/npm/__snapshots__/index.spec.ts.snap

lib/config/presets/npm/index.spec.ts