Fix NPE when the "isProxy" method returns null

[nichiporenko]

Fix the NullPointerException since cxConnectionDetails.isProxy() has null value and we see the following:

12:14:54 ERROR: Build step failed with exception
12:14:54 java.lang.NullPointerException
12:14:54 	at com.checkmarx.jenkins.CxScanBuilder.resolveConfiguration(CxScanBuilder.java:1300)
12:14:54 	at com.checkmarx.jenkins.CxScanBuilder.perform(CxScanBuilder.java:870)
12:14:54 	at jenkins.tasks.SimpleBuildStep.perform(SimpleBuildStep.java:123)
12:14:54 	at hudson.tasks.BuildStepCompatibilityLayer.perform(BuildStepCompatibilityLayer.java:80)
12:14:54 	at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
12:14:54 	at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:803)
12:14:54 	at hudson.model.Build$BuildExecution.build(Build.java:197)
12:14:54 	at hudson.model.Build$BuildExecution.doRun(Build.java:163)
12:14:54 	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:513)
12:14:54 	at hudson.model.Run.execute(Run.java:1906)
12:14:54 	at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
12:14:54 	at hudson.model.ResourceController.execute(ResourceController.java:97)
12:14:54 	at hudson.model.Executor.run(Executor.java:429)
12:14:54 Build step 'Execute Checkmarx Scan' marked build as failure

The cxConnectionDetails.isProxy() method returns value of Big Boolean which can be null (and it is).
In version 2020.4.3 everything works fine.

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[nichiporenko]

Hi dear maintainers,

Did you have a chance to check this update?

Best Regards,
Dmitry