Fixes "Undefined variable" in migration:status

Fixes "Undefined variable: oldestMigrationTimestamp" when running "migration:status" without "-v"

The variable $oldestMigrationTimestamp is set on line 96 only when the verbose option is passed. Because of this, when the code reaches line 129 and tries to access $oldestMigrationTimestamp, the variable is not set, causing an error.