v3.0: Sort in **descending** stake order (backport of #8787)

[mergify]

Problem

• stake-weighted sorting with some randomness was doing it backward
  • ignore randomness for now, assume rng always return 0.5
  • 2 nodes, stake=1, stake=2
  • weights = 0.5^(1/1) = 0.5
  • weights = 0.5^(1/2) = 0.707
  • node with stake 2 would come 2nd in list

Summary of Changes

• reverse the sort comparison

Fixes #

---

This is an automatic backport of pull request #8787 done by [Mergify](https://mergify.com).

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.4%. Comparing base (3454667) to head (2036d12).

Additional details and impacted files

@@           Coverage Diff           @@
##             v3.0    #8805   +/-   ##
=======================================
  Coverage    83.4%    83.4%           
=======================================
  Files         810      810           
  Lines      366213   366213           
=======================================
+ Hits       305677   305701   +24     
+ Misses      60536    60512   -24     

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[t-nelson]

out of an abundance of caution, we want to see this on testnet for a bit before accepting this one