test: add more comprehensive tests for FeeVote

[mvadari]

High Level Overview of Change

This PR, as the title says, adds more comprehensive tests for the FeeVote module.

Previously, the tests only checked the basics, and not the more comprehensive flows in that class.

There is no source code change in this PR.

Context of Change

In preparation for #5600 - instead of including these (not-feature-specific) tests in that PR, I'd prefer to just add the Smart Escrow-specific tests there, making it easier to review (and decreasing the diff a bit).

Type of Change

• Tests (you added tests for code that already exists, or your new feature included in this PR)

Test Plan

This PR is only tests. The tests pass in CI.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.9%. Comparing base (cfd26f4) to head (de9a1c6).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #5746   +/-   ##
=======================================
  Coverage     78.9%   78.9%           
=======================================
  Files          816     816           
  Lines        72246   72246           
  Branches      8418    8418           
=======================================
+ Hits         56993   56994    +1     
+ Misses       15253   15252    -1     

see 7 files with indirect coverage changes

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[vvysokikh1]

I understand that XRPFees was enabled around 1.5 years ago, so the legacy behavior is kind of supported, but I'm not sure adding legacy behavior tests at this point makes any sense

[mvadari]

I understand that XRPFees was enabled around 1.5 years ago, so the legacy behavior is kind of supported, but I'm not sure adding legacy behavior tests at this point makes any sense

I can remove that part if you'd like (it was more for full codecov etc). IMO the more important aspect is the fee voting tests, as fee voting does still need to happen every flag ledger.

[vvysokikh1]

I understand that XRPFees was enabled around 1.5 years ago, so the legacy behavior is kind of supported, but I'm not sure adding legacy behavior tests at this point makes any sense

I can remove that part if you'd like (it was more for full codecov etc). IMO the more important aspect is the fee voting tests, as fee voting does still need to happen every flag ledger.

I don't have a strong call on this, just a general remark, so this is up to you. Personally I think those are not worth adding at this point.

[vvysokikh1]

lgtm!