Solve duplicated network issues for ephemeral VMs

[nesitor]

Problem: If the service restarts, the diagnostic VM fails for network issues.

Solution: Loading already loaded VMs filtering by only persistent ones. Also remove the network interface if exists and re-create it.

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 61.45%. Comparing base (2f68012) to head (c320752).
Report is 6 commits behind head on main.

Files	Patch %	Lines
src/aleph/vm/network/interfaces.py	50.00%	5 Missing and 1 partial ⚠️
src/aleph/vm/pool.py	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #680      +/-   ##
==========================================
+ Coverage   61.44%   61.45%   +0.01%     
==========================================
  Files          68       68              
  Lines        5994     5993       -1     
  Branches      635      633       -2     
==========================================
  Hits         3683     3683              
  Misses       2156     2156              
+ Partials      155      154       -1     

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