feat: use the scaled power for winning tickets

[Stebalien]

This brings us in-line with the FIP.

[Stebalien]

Note: we can't throw away the unscaled powers because we need them for:

1. Re-calculating power scaling (unfortunately, due to how our tests are written, we need the ability to add entries to the power table).
2. Commit to the power table, etc.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.07%. Comparing base (2ddf410) to head (5516b94).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #375   +/-   ##
=======================================
  Coverage   83.07%   83.07%           
=======================================
  Files          15       15           
  Lines        1778     1778           
=======================================
  Hits         1477     1477           
  Misses        175      175           
  Partials      126      126           

Files	Coverage Δ
gpbft/gpbft.go	85.22% <100.00%> (ø)
gpbft/message_builder.go	75.38% <100.00%> (ø)
gpbft/powertable.go	86.66% <100.00%> (ø)