Orphan kernel threads needs to check process validity before access

[atcuno]

Another backtrace triggered in mass testing:

 File "/home/ub/volatility3/volatility3/cli/__init__.py", line 501, in run
    renderer.render(grid)
  File "/home/ub/volatility3/volatility3/cli/text_renderer.py", line 232, in render
    grid.populate(visitor, outfd)
  File "/home/ub/volatility3/volatility3/framework/renderers/__init__.py", line 241, in populate
    for level, item in self._generator:
  File "/home/ub/volatility3/volatility3/framework/plugins/windows/thrdscan.py", line 100, in _generator
    for ethread in self.implementation(self.context, kernel_name):
  File "/home/ub/volatility3/volatility3/framework/plugins/windows/orphan_kernel_threads.py", line 84, in list_orphan_kernel_threads
    if proc.UniqueProcessId != 4 and proc.InheritedFromUniqueProcessId != 4:
       ^^^^^^^^^^^^^^^^^^^^