refactor(minor-rewards): param updates take effect in current epoch

[cjcobb23]

There was too much complexity around when parameter updates take effect. Sometimes they took effect in the current epoch, and sometimes they took effect in the next epoch, and it was hard to reason about when each happened. Instead, I think it is simpler and easier to maintain by having parameter updates always take effect in the current epoch.

https://axelarnetwork.atlassian.net/browse/AXE-5297

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 93.68%. Comparing base (8b0df43) to head (473cc49). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #639 +/- ## ========================================== + Coverage 93.61% 93.68% +0.07% ========================================== Files 243 243 Lines 35226 35647 +421 ========================================== + Hits 32976 33397 +421 Misses 2250 2250 ```

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