chore(types): Fix error type and clean up interface definition

[rezbera]

Error message for Blobs decoding was incorrectly using messages meant for beacon blocks

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 32.31%. Comparing base (70cb888) to head (c37e5fe).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
consensus/cometbft/service/encoding/encoding.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2515   +/-   ##
=======================================
  Coverage   32.31%   32.31%           
=======================================
  Files         350      350           
  Lines       15670    15670           
  Branches       20       20           
=======================================
  Hits         5063     5063           
  Misses      10244    10244           
  Partials      363      363           

Files with missing lines	Coverage Δ
consensus/cometbft/service/encoding/encoding.go	0.00% <0.00%> (ø)