Fix a regression bug inside windows network_manager

[Miauwkeru]

Found a regression inside #870 in the case a registry key doesn't exist or is empty.
I made a small fix for it here, however I also noticed the types aren't correct either. Will save that for another moment

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 77.03%. Comparing base (a75083f) to head (7ea5eca).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
dissect/target/plugins/os/windows/network.py	40.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #936      +/-   ##
==========================================
- Coverage   77.03%   77.03%   -0.01%     
==========================================
  Files         322      322              
  Lines       27603    27604       +1     
==========================================
  Hits        21265    21265              
- Misses       6338     6339       +1     

Flag	Coverage Δ
unittests	77.03% <40.00%> (-0.01%)	⬇️

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[twiggler]

The fix looks ok.
Since it is nice to get this before the next release I approve it.

Can you create a ticket to:

• add/adjust the unit test for when extract_network_device_config returns nothing
• Make the return type of _extract_network_device_config more meaningful, for example by adding data classes
• Improve the readability of the _interfaces method of WindowsNetworkPlugin