fix: wave meta file delta generation

[scolladon]

What does this pull request contain?

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• Added (for new features).
• Changed (for changes in existing functionality).
• Deprecated (for soon-to-be removed features).
• Removed (for now removed features).
• Fixed (for any bug fixes).
• Security (for vulnerability fixes).

Explain your changes

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Make sure the extension is taken into account when copying metafile

Does this close any currently open issues?

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closes #286

• Jest test added to check the fix is applied.

[codecov]

Codecov Report

Merging #293 (d627202) into main (001c07e) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main      #293   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           23        23           
  Lines          634       633    -1     
=========================================
- Hits           634       633    -1     

Impacted Files	Coverage Δ
src/service/waveHandler.js	100.00% <ø> (ø)
src/service/standardHandler.js	100.00% <100.00%> (ø)

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[codeclimate]

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