Handle dust scenario in claimer target price

[trmid]

This PR adds an additional fix to the logic change in #33. Please refer to #33 for the full issue context.

The claim fees now ramp up to the tier-specific maxFee instead of the previous highFee over the timeToReachMaxFee period. The highFee was based on the n-3 prize size, which is not guaranteed to have significant value every draw. This change ensures that the maxFee will be reached for every tier sometime in the auction time period, even if the higher tiers have insignificant value.

[linear]

GEN-1834 Handle dust scenario in claimer target price

[github-actions]

LCOV of commit 21a9ed6 during Tests with 100% Coverage #160

Summary coverage rate:
  lines......: 100.0% (89 of 89 lines)
  functions..: 100.0% (16 of 16 functions)
  branches...: no data found

Files changed coverage rate:
                                  |Lines       |Functions  |Branches    
  Filename                        |Rate     Num|Rate    Num|Rate     Num
  ======================================================================
  src/Claimer.sol                 | 100%     58| 100%    10|    -      0