Transforms RandomForest estimators non-consecutive labels to consecutive labels where appropriate

[VamsiTallam95]

This PR closes #4478 by transforming non-consecutive labels outside of [0,n) to consecutive labels inside [0,n) similar to what Scikit-learn does under the hood.

Closes #691

[ayushdg]

rerun tests

[VamsiTallam95]

rerun tests

[VamsiTallam95]

rerun tests

[VamsiTallam95]

rerun tests

[codecov-commenter]

Codecov Report

Merging #4780 (8cd8d3a) into branch-22.08 (b26fe7e) will increase coverage by 0.00%. The diff coverage is n/a.

@@              Coverage Diff              @@
##           branch-22.08    #4780   +/-   ##
=============================================
  Coverage         77.62%   77.62%           
=============================================
  Files               180      180           
  Lines             11382    11384    +2     
=============================================
+ Hits               8835     8837    +2     
  Misses             2547     2547           

Flag	Coverage Δ
dask	45.52% <ø> (+<0.01%)	:arrow_up:
non-dask	67.26% <ø> (+<0.01%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
python/cuml/metrics/__init__.py	100.00% <0.00%> (ø)
python/cuml/metrics/cluster/__init__.py	100.00% <0.00%> (ø)
python/cuml/thirdparty_adapters/adapters.py	91.48% <0.00%> (ø)

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[beckernick]

Is this ready for another round of reviews?

[VamsiTallam95]

Its ready!

[lowener]

rerun tests

[lowener]

rerun tests

[beckernick]

Changing the title before merging, as this PR only applies this change to random forest models.

[beckernick]

This will also close https://github.com/rapidsai/cuml/issues/691

[dantegd]

@gpucibot merge