fix: wrong TransactionIndex in receipt

[mmsqe]

Description

this change shouldn't have been added in #589

Closes: #XXXX

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• tackled an existing issue or discussed with a team member
• left instructions on how to review the changes
• targeted the main branch

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.20%. Comparing base (5217b59) to head (b1e720e).
⚠️ Report is 1 commits behind head on main.

❌ Your project status has failed because the head coverage (65.20%) is below the target coverage (90.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #806      +/-   ##
==========================================
+ Coverage   64.12%   65.20%   +1.08%     
==========================================
  Files         317      317              
  Lines       21717    21598     -119     
==========================================
+ Hits        13927    14084     +157     
+ Misses       6472     6353     -119     
+ Partials     1318     1161     -157     

Files with missing lines	Coverage Δ
rpc/backend/comet_to_eth.go	80.74% <100.00%> (ø)

... and 19 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.