V5 Mark code breaks if assignedCondition is null / undefined

[danoswaltCL]

Version where bug was found:
"5.1"

Describe the bug
Java Client will fail if attempting to mark a site and target as null new MarkRequestData(site, target) constructor. The validator correctly sees this object as optional, but the code breaks when trying to do null-coalescing due to the nested nature of this object. This fix addresses proper null coalescing when

To Reproduce
Steps to reproduce the behavior:

1. In Main.java you can reproduce by marking an object using new MarkRequestData(site, target) constructor, which should be recorded as a default null condition, but instead breaks due to assignedCondition object being undefined and not handled with proper null checking in the code.

Expected behavior
We should be able to mark null in the expected way in the Java Client.

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.