Splat optimizations cause metadata to be dropped when not leveraging `winston.formats.splat()`

mwe.js

const logger = winston.createLogger({
  level: "debug",
  defaultMeta: { id: 'APP', service: 'Authentication' },
  transports: [mockTransports.inMemory(actualOutput)]
});

logger.info('this is a test', { extraThing: 7 });
logger.info('this is %c a test', { extraThing: 7 });

assume(actualOutput.every((msg) =>
    msg.hasOwnProperty("extraThing")
)).is.true("Not all messages include the additional metadata")