fix(metagen): client file upload fixup

[luckasRanarison]

• Make reusable file on multiple path for python and added tests for TS and Python.

Migration notes

---

• The change comes with new or modified tests
• Hard-to-understand functions have explanatory comments
• End-user documentation is updated to reflect the change

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.81%. Comparing base (3643286) to head (8c8909d).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #936   +/-   ##
=======================================
  Coverage   77.81%   77.81%           
=======================================
  Files         153      153           
  Lines       18960    18960           
  Branches     1893     1894    +1     
=======================================
  Hits        14754    14754           
  Misses       4182     4182           
  Partials       24       24           

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