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]

Codecov Report

All modified and coverable lines are covered by tests ✅

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

Additional details and impacted files

@@            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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[cgorenflo]

as far as I can tell your tests cover the edge cases and because distribution is trailing behind 2 epochs it's probably ok to change the current epoch params, but please make sure you really thought it through completely (I'm not deeply enough versed in rewards at the moment to speak with confidence). One thing to consider: what happens if the epoch shortens enough that new epochs are three times or more shorter? Do we cut multiple epochs that will be immediately eligible for distribution or do we just cut the current epoch short to this block and start a new one?