Problem: patch gasUsed for eth_getTransactionReceipt is not correct

[mmsqe]

this bug was introduced in https://github.com/evmos/ethermint/pull/1557/files

Closes: #XXX

Description

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For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 62.56%. Comparing base (a97cd08) to head (ac48f37).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #434   +/-   ##
========================================
  Coverage    62.56%   62.56%           
========================================
  Files          130      130           
  Lines        12512    12512           
========================================
  Hits          7828     7828           
  Misses        4138     4138           
  Partials       546      546           

Files	Coverage Δ
rpc/backend/tx_info.go	63.96% <100.00%> (ø)