Meliora Testlab Pipeline steps dropped from 2.481 builds

[MarkEWaite]

Reproduction steps

1. The upgrade from Java EE 8 to Jakarta EE 9 has caused the Pipeline steps documentation generator to report a null pointer exception while trying to extract the Pipeline steps for the plugin.

The ci.jenkins.io logfile reports:

21:19:04  [WARNING] Cannot instantiate fi.meliora.testlab.ext.jenkins.TestlabNotifier$DescriptorImpl 
21:19:04  java.lang.NullPointerException: Cannot invoke "jakarta.servlet.ServletContext.getAttribute(String)" because "c" is null
21:19:04  	at hudson.util.PluginServletFilter.getInstance(PluginServletFilter.java:87)
21:19:04  	at hudson.util.PluginServletFilter.addFilter(PluginServletFilter.java:115)
21:19:04  	at hudson.util.PluginServletFilter.addFilter(PluginServletFilter.java:134)
21:19:04  	at PluginClassLoader for meliora-testlab//fi.meliora.testlab.ext.jenkins.TestlabNotifier$DescriptorImpl.<init>(TestlabNotifier.java:682)

Expected Results

Pipelines steps documentation for plugin should be generated

Actual Results

Pipeline steps are not generated.

Anything else?

I've submitted a pull request that may resolve the issue:

• Require Jenkins 2.452.4 or newer (modernize) jenkinsci/meliora-testlab-plugin#17