Bump mqtt from 5.15.1 to 5.15.2

Bumps [mqtt](https://github.com/mqttjs/MQTT.js) from 5.15.1 to 5.15.2.
- [Release notes](https://github.com/mqttjs/MQTT.js/releases)
- [Changelog](https://github.com/mqttjs/MQTT.js/blob/main/CHANGELOG.md)
- [Commits](mqttjs/MQTT.js@v5.15.1...v5.15.2)

---
updated-dependencies:
- dependency-name: mqtt
  dependency-version: 5.15.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]