Fixed model saving when git repo not found

[scap3yvt]

Fixes #723

Proposed Changes

• added another type of exception check during model saving

Checklist

• I have read the CONTRIBUTING guide.
• My PR is based from the current GaNDLF master .
• Non-breaking change (does not break existing functionality): provide as many details as possible for any breaking change.
• Function/class source code documentation added/updated.
• Code has been blacked for style consistency.
• If applicable, version information has been updated in GANDLF/version.py.
• If adding a git submodule, add to list of exceptions for black styling in pyproject.toml file.
• Usage documentation has been updated, if appropriate.
• Tests added or modified to cover the changes; if coverage is reduced, please give explanation.
• If customized dependency installation is required (i.e., a separate pip install step is needed for PR to be functional), please ensure it is reflected in all the files that control the CI, namely: python-test.yml, and all docker files [1,2,3].

[github-actions]

MLCommons CLA bot All contributors have signed the MLCommons CLA ✍️ ✅

[scap3yvt]

CLA has been signed.

[sarthakpati]

Thank you for your interest in contributing to GaNDLF! 😄

[sarthakpati]

LGTM

[codecov]

Codecov Report

Merging #729 (b97fb05) into master (d099b7b) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master     #729   +/-   ##
=======================================
  Coverage   94.70%   94.70%           
=======================================
  Files         117      117           
  Lines        8221     8221           
=======================================
  Hits         7786     7786           
  Misses        435      435           

Flag	Coverage Δ
unittests	94.70% <0.00%> (ø)

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

Files	Coverage Δ
GANDLF/utils/modelio.py	84.21% <0.00%> (ø)

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