PreEstabilishedSystemTitle null

[kyakan]

Description of the issue:

In the .NET implementation, when the ServerSystemTitle is set, the PreEstablishedSystemTitle is automatically updated. However, this behavior is not present in the Java version.

.NET reference:
https://github.com/Gurux/Gurux.DLMS.Net/blob/c4290171bdc67d51949c9b9de2be1aa9aee30e27/Development/Secure/GXDLMSSecureClient.cs#L165

Java reference:

Gurux.DLMS.Android/Java/DLMS/src/main/java/gurux/dlms/GXDLMS.java

Lines 1493 to 1495 in 2f01fa4

	// General protection can be used with pre-established
	// connections.
	&& ((p.getSettings().getPreEstablishedSystemTitle() == null

Additionally, in Java, it's not possible to use general protection under certain conditions, as highlighted in the provided link.
Proposed solution:

Align the Java behavior with the .NET version by ensuring that setting the ServerSystemTitle also updates the PreEstablishedSystemTitle.