Storage definition changes export to Git repo

[isc-pbarton]

fixes #906

Tested:

• editing a persistent class to add a new property, storage definition in git repo is updated after save
• editing a persistent class to add a new parameter, export after save still works and is not called twice
• editing a non-persistent class, export after save still works and is not called twice

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.09%. Comparing base (04c5f8a) to head (f4e34d4).

Files with missing lines	Patch %	Lines
cls/SourceControl/Git/Extension.cls	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #910      +/-   ##
==========================================
- Coverage   50.19%   50.09%   -0.11%     
==========================================
  Files          24       24              
  Lines        3315     3322       +7     
==========================================
  Hits         1664     1664              
- Misses       1651     1658       +7     

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