Problem: get unnecessary block result when only need header

[mmsqe]

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

Attention: Patch coverage is 80.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 60.06%. Comparing base (dbc7eb4) to head (795dc52).

Files with missing lines	Patch %	Lines
rpc/backend/blocks.go	76.47%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #526      +/-   ##
===========================================
- Coverage    60.07%   60.06%   -0.02%     
===========================================
  Files          128      128              
  Lines         9827     9829       +2     
===========================================
  Hits          5904     5904              
- Misses        3342     3343       +1     
- Partials       581      582       +1     

Files with missing lines	Coverage Δ
rpc/backend/utils.go	49.71% <100.00%> (ø)
rpc/backend/blocks.go	81.94% <76.47%> (-0.58%)	⬇️