fix netmask

[jneilliii]

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What does this PR do and why is it necessary?

in netifaces2 netmask was replaced with mask

How was it tested? How can it be tested by the reviewer?

manually modified in local deployment and ran OctoPrint

Any background context you want to provide?

What are the relevant tickets if any?

#5005

Screenshots (if appropriate)

Further notes

[steve1515]

I have a couple of comments for this PR...

1. I think you might also want to update references to netmask in the function here:

   OctoPrint/tests/util/test_net.py

   Line 17 in fed2dd7

   def patched_ifaddresses(addr):

2. I'm unclear what happens when both netifaces and netifaces2 exists and how netifaces2 is insured to be loaded.
   Should we have a check for mask and netmask and use the one that exists? Or are we sure netifaces2 will always be used when both exist?

[foosel]

I've decided against going with the easiest approach here, exactly because I'm not sure either if it's not possible to still load netifaces out there if it is installed in parallel. So instead, we'll go with 7d80170, which is more resilient against parallel loading (and also has the unit tests adjusted as needed).