Fix ESXi OS when no local state exists yet

[Schamper]

When the hypervisor is not fully installed yet, the local state file may not exist yet.

[codecov]

Codecov Report

Attention: Patch coverage is 81.25000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 75.26%. Comparing base (e3becf6) to head (456c211).

Files	Patch %	Lines
dissect/target/plugins/os/unix/esxi/_os.py	81.25%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #784      +/-   ##
==========================================
- Coverage   75.26%   75.26%   -0.01%     
==========================================
  Files         296      296              
  Lines       25573    25575       +2     
==========================================
  Hits        19248    19248              
- Misses       6325     6327       +2     

Flag	Coverage Δ
unittests	75.26% <81.25%> (-0.01%)	⬇️

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