EIP-1559: fix migration handler to update min base fee

[jewei1997]

Describe your changes and provide context

Migration handler should update min base fee to 1gwei

Testing performed to validate your change

unit tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.19%. Comparing base (4daa00c) to head (a81b435).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1891      +/-   ##
==========================================
+ Coverage   61.17%   61.19%   +0.01%     
==========================================
  Files         263      263              
  Lines       23310    23311       +1     
==========================================
+ Hits        14260    14265       +5     
+ Misses       8043     8040       -3     
+ Partials     1007     1006       -1     

Files with missing lines	Coverage Δ
x/evm/migrations/migrate_eip_1559_params.go	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes