build(deps): bump mqtt in /apps/ecars-realtime/packages/ecars-mqtt-agent

Bumps [mqtt](https://github.com/mqttjs/MQTT.js) from 4.3.7 to 5.5.0.
- [Release notes](https://github.com/mqttjs/MQTT.js/releases)
- [Changelog](https://github.com/mqttjs/MQTT.js/blob/main/CHANGELOG.OLD.md)
- [Commits](mqttjs/MQTT.js@v4.3.7...v5.5.0)

---
updated-dependencies:
- dependency-name: mqtt
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>