fix(log): demote log level to DEBUG on skipping forwards based on cert

[hanabi1224]

When bootstrapping a Forest or Lotus node from scratch with the latest snapshot (mostly on CI), F3 downloads certificates from instance 0 and floods stdout with tons of skipping forwards based on cert.

This PR proposes demoting its log level to DEBUG as it does not seem to be as important as other INFO logs under f3.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.01%. Comparing base (322dc35) to head (9db8a7c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #724      +/-   ##
==========================================
- Coverage   75.23%   75.01%   -0.22%     
==========================================
  Files          69       69              
  Lines        6928     6928              
==========================================
- Hits         5212     5197      -15     
- Misses       1306     1317      +11     
- Partials      410      414       +4     

Files with missing lines	Coverage Δ
host.go	63.85% <100.00%> (-1.81%)	⬇️

... and 3 files with indirect coverage changes