Make IBC precompile nonpayable

[dssei]

Describe your changes and provide context

Make IBC precompile nonpayable. It was defined as such in solidity, but not in ABI + added enforcement in code.

Testing performed to validate your change

• unit test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.50%. Comparing base (223a234) to head (abaa75e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2032      +/-   ##
==========================================
+ Coverage   61.47%   61.50%   +0.02%     
==========================================
  Files         264      264              
  Lines       24565    24568       +3     
==========================================
+ Hits        15101    15110       +9     
+ Misses       8335     8328       -7     
- Partials     1129     1130       +1     

Files with missing lines	Coverage Δ
precompiles/ibc/ibc.go	47.31% <100.00%> (+0.53%)	⬆️

... and 2 files with indirect coverage changes