fix: translate the keypath values of the background and avatars modal

[brenopolanski]

Summary

Fixes #1664.

Checklist

• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[luciorubeens]

You also need to mock this strings_snakeCase method directly in the SelectionBackground.spec.js file or in the setup: https://github.com/ArkEcosystem/desktop-wallet/blob/develop/__tests__/unit/__utils__/setup.js.

[codecov]

Codecov Report

Merging #1665 into develop will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff            @@
##           develop    #1665   +/-   ##
========================================
  Coverage    62.95%   62.95%           
========================================
  Files          135      135           
  Lines         3663     3663           
  Branches       767      767           
========================================
  Hits          2306     2306           
  Misses        1134     1134           
  Partials       223      223

Impacted Files	Coverage Δ
...erer/components/Selection/mixin-selection-image.js	68.18% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update bda0e3a...7bc9c69. Read the comment docs.