[network] Bridges with long names use hash suffix

[levkropp]

This pull request introduces a new strategy for generating bridge names in the Linux backend to ensure uniqueness when interface names are long by truncating long interface names and appending a short hash. This ensures that bridge names are both readable and unique.

• Updated the bridge creation logic in create_bridge_with to use the new generate_bridge_name function, replacing the previous simple truncation method.
• Added QCryptographicHash includes to both backend_utils.cpp and test_backend_utils.cpp to support the new hashing logic for bridge name generation.

Originally:

• eth123456789abc → br-eth123456789 (truncated to 15 chars)
• eth123456789xyz → br-eth123456789 (same name - collision)

With the fix:

• eth123456789abc → br-eth12345-8f9 (unique hash suffix)
• eth123456789xyz → br-eth12345-a2c (different hash - no collision)

Short names (unchanged, fully readable):

• eth0 → br-eth0
• wlan0 → br-wlan0
• enp0s3 → br-enp0s3

resolves #2158

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.39%. Comparing base (96a02d6) to head (4a070df).
⚠️ Report is 14 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4422   +/-   ##
=======================================
  Coverage   89.39%   89.39%           
=======================================
  Files         253      253           
  Lines       16457    16468   +11     
=======================================
+ Hits        14711    14722   +11     
  Misses       1746     1746           

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