Catch ValueError in module available

[ethanwharris]

What does this PR do?

Fixes #614

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[codecov]

Codecov Report

Merging #615 (d6ce1fb) into master (0890270) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #615      +/-   ##
==========================================
- Coverage   89.98%   89.96%   -0.03%     
==========================================
  Files         149      149              
  Lines        8456     8458       +2     
==========================================
  Hits         7609     7609              
- Misses        847      849       +2     

Flag	Coverage Δ
gpu	?
pytest	?
unittests	89.96% <0.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
flash/core/utilities/imports.py	89.81% <0.00%> (-1.70%)	⬇️

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