Use of TLS

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- [ ] Bug exists Release Version 1.2.5 ( Master Branch)
- [x] Bug exists in MQTTv3 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)
- [ ] Bug exists in MQTTv5 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)

During an empirical study to understand the nature of cryptographic misuses in enterprise-driven projects on GitHub, we randomly inspected a few of the misuses. One of the misuses for which we could confirm as a true positive of the analysis, [CogniCryptSAST](https://github.com/CROSSINGTUD/CryptoAnalysis), is in this project.
In the class [SSLSocketFactoryFactory](https://github.com/eclipse/paho.mqtt.java/blob/6f35dcb785597a6fd49091efe2dba47513939420/org.eclipse.paho.client.mqttv3/src/main/java/org/eclipse/paho/client/mqttv3/internal/security/SSLSocketFactoryFactory.java#L137) the default protocol is set to TLS. Other analyses, like [SonarSource](https://rules.sonarsource.com/java/RSPEC-44230) also mark the usage of TLS as critical.

**Expected behavior:** A secure protocol
**Observed behavior:** An insecure protocol

**How to Reproduce:**
- Apply CogniCryptSAST to the project
- Inspect the misuses reported