Fix TxIndex wrongly when trace first Tx of a block (backport #1187)

[mergify]

This is an automatic backport of pull request #1187 done by Mergify.
Cherry-pick of cd41c48 has failed:

On branch mergify/bp/release/v0.17.x/pr-1187
Your branch is up to date with 'origin/release/v0.17.x'.

You are currently cherry-picking commit cd41c48.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   x/evm/keeper/grpc_query.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   CHANGELOG.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[codecov]

Codecov Report

Merging #1195 (265feee) into release/v0.17.x (f740e13) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@                 Coverage Diff                 @@
##           release/v0.17.x    #1195      +/-   ##
===================================================
+ Coverage            61.80%   61.81%   +0.01%     
===================================================
  Files                   90       90              
  Lines                 7320     7322       +2     
===================================================
+ Hits                  4524     4526       +2     
  Misses                2573     2573              
  Partials               223      223              

Impacted Files	Coverage Δ
x/evm/keeper/grpc_query.go	69.38% <100.00%> (+0.13%)	⬆️