no auth causes npe

[kortemik]

Describe the bug
when authentication is not set, one will get npe out of
sdElement.addSDParam("subject", subject);

03.05.2024 14:06:09.529 [ERROR] [com.teragrep.lsh_01.RelpConversion] [http-input-handler-executor[T#1]] Unexpected error when sending a message: <Cannot invoke "String.length()" because "paramValue" is null> java.lang.NullPointerException: Cannot invoke "String.length()" because "paramValue" is null
        at com.teragrep.rlo_14.SyslogMessage.getEscapedParamValue(SyslogMessage.java:273)
        at com.teragrep.rlo_14.SyslogMessage.writeSDElements(SyslogMessage.java:265)
        at com.teragrep.rlo_14.SyslogMessage.toRfc5424SyslogMessage(SyslogMessage.java:248)
        at com.teragrep.rlo_14.SyslogMessage.toRfc5424SyslogMessage(SyslogMessage.java:207)
        at com.teragrep.lsh_01.RelpConversion.sendMessage(RelpConversion.java:191)
        at com.teragrep.lsh_01.RelpConversion.onNewMessage(RelpConversion.java:81)
        at com.teragrep.lsh_01.MessageProcessor.processMessage(MessageProcessor.java:139)
        at com.teragrep.lsh_01.MessageProcessor.run(MessageProcessor.java:121)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
        at java.base/java.lang.Thread.run(Thread.java:840)

same goes for

        for (Map.Entry<String, String> header : headers.entrySet()) {
            headerSDElement.addSDParam(new SDParam(header.getKey(), header.getValue()));
        }

Expected behavior
no npe, empty element.

How to reproduce
send message without authentication set

Screenshots

Software version
3.1.1

Desktop (please complete the following information if relevant):

• OS:
• Browser:
• Version:

Additional context

[kortemik]

lsh_01-test-plan.zip

[kortemik]

can the sdElement.addSDParam("subject", subject); still cause it?

[51-code]

sdElement.addSDParam("subject", subject); can't cause an NPE.
The Subject is created in MessageProcessor, either as an empty string (SubjectAnonymous) or an actual string (SubjectImpl). SubjectImpl is only created through BasicAuthentication for now, and there, the asSubject() method checks for null values and throws an IllegalArgumentException if that is the case.