bug: avoid network calls in disconnected environments when loading model from cache

[m-misiura]

This PR deals with RHOAIENG-54559

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 40.00000% with 15 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@20b3945). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
nemoguardrails/embeddings/providers/fastembed.py	40.00%	15 Missing ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##             develop      #38   +/-   ##
==========================================
  Coverage           ?   76.88%           
==========================================
  Files              ?      200           
  Lines              ?    20412           
  Branches           ?        0           
==========================================
  Hits               ?    15693           
  Misses             ?     4719           
  Partials           ?        0           

Flag	Coverage Δ
python	76.88% <40.00%> (?)

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Files with missing lines	Coverage Δ
nemoguardrails/embeddings/providers/fastembed.py	60.78% <40.00%> (ø)

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