fix: empty inFile metadata detection

[scolladon]

Explain your changes

---

Fix empty check
Improve spec

Does this close any currently open issues?

---

closes #

• Jest tests added to cover the fix.
• NUT tests added to cover the fix.
• E2E tests added to cover the fix.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (ca6d5a7) 100.00% compared to head (b24d889) 100.00%.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #683   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           34        34           
  Lines          952       952           
=========================================
  Hits           952       952           

Files Changed	Coverage Δ
src/utils/metadataDiff.js	100.00% <100.00%> (ø)

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[codeclimate]

Code Climate has analyzed commit b24d889 and detected 0 issues on this pull request.

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[github-actions]

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