Return details from TargetDistributionDataCheck as floats rather string

[angela97lin]

Closes #2943. I chose not to keep the string representation and moved the calculations into a separate helper method, but open to discussion if we feel like the string representation is helpful in addition to the float values.

[codecov]

Codecov Report

Merging #3085 (4db17e3) into main (3831e33) will increase coverage by 0.1%.
The diff coverage is 100.0%.

@@           Coverage Diff           @@
##            main   #3085     +/-   ##
=======================================
+ Coverage   99.8%   99.8%   +0.1%     
=======================================
  Files        313     313             
  Lines      30468   30470      +2     
=======================================
+ Hits       30378   30380      +2     
  Misses        90      90             

Impacted Files	Coverage Δ
...hecks_tests/test_target_distribution_data_check.py	100.0% <ø> (ø)
...alml/data_checks/target_distribution_data_check.py	100.0% <100.0%> (ø)

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[angela97lin]

Moving mathy-implementation chunk into helper method to make validate easier to read!

[jeremyliweishih]

very nice!