tests(dist): Add ClaimRewards unit and event tests

[Vvaradinov]

Description

This PR adds unit and event tests for the new ClaimRewards transaction in the distribution extension.

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Closes ENG-2235

[codecov]

Codecov Report

Merging #1954 (1167cf6) into main (61129ee) will increase coverage by 0.18%.
The diff coverage is 100.00%.

❗ Current head 1167cf6 differs from pull request most recent head 6881cd4. Consider uploading reports for the commit 6881cd4 to get more accurate results

@@            Coverage Diff             @@
##             main    #1954      +/-   ##
==========================================
+ Coverage   69.77%   69.95%   +0.18%     
==========================================
  Files         327      327              
  Lines       24268    24243      -25     
==========================================
+ Hits        16933    16960      +27     
+ Misses       6470     6413      -57     
- Partials      865      870       +5     

Files	Coverage Δ
precompiles/distribution/tx.go	63.41% <100.00%> (+17.07%)	⬆️
precompiles/distribution/types.go	92.78% <ø> (+6.25%)	⬆️

... and 3 files with indirect coverage changes

[linear]

ENG-2235 ClaimRewards Unit Tests