fix: prevent nil pointer dereference on BLOBBASEFEE opcode

[XinyuCRO]

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 40.32%. Comparing base (e43268a) to head (49c68b8).

Additional details and impacted files

@@                 Coverage Diff                 @@
##           release/v0.23.x     #875      +/-   ##
===================================================
+ Coverage            40.30%   40.32%   +0.02%     
===================================================
  Files                  190      190              
  Lines                15647    15651       +4     
===================================================
+ Hits                  6306     6311       +5     
+ Misses                8658     8649       -9     
- Partials               683      691       +8     

Files with missing lines	Coverage Δ
rpc/types/types.go	7.89% <100.00%> (+7.89%)	⬆️
x/evm/keeper/config.go	91.42% <100.00%> (+0.12%)	⬆️
x/evm/keeper/state_transition.go	76.42% <100.00%> (+0.09%)	⬆️

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