Adjust EarnerRateModel to be less conservative

[toninorair]

Adjust EarnerRate to be less conservative. Particularly if earnerRate <= minterRate, and no deactivated were in the system, return earnerRate

With current state of protocol where minterRate == TTG set earnerRate, effective earner rate does not require safety rate multiplier adjustments

[github-actions]

LCOV of commit fa60bcc during Forge Coverage #618

Summary coverage rate:
  lines......: 98.6% (547 of 555 lines)
  functions..: 96.3% (129 of 134 functions)
  branches...: no data found

Files changed coverage rate:
                                     |Lines       |Functions  |Branches    
  Filename                           |Rate     Num|Rate    Num|Rate     Num
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  src/rateModels/EarnerRateModel.sol |17.2%     29| 0.0%     3|    -      0