Remove imblearn from Oversampler attribute

[eccabay]

Closes #2754

[codecov]

Codecov Report

Merging #2755 (fdd390b) into main (e3ec96f) will increase coverage by 0.1%.
The diff coverage is 100.0%.

@@           Coverage Diff           @@
##            main   #2755     +/-   ##
=======================================
+ Coverage   99.9%   99.9%   +0.1%     
=======================================
  Files        301     301             
  Lines      27840   27851     +11     
=======================================
+ Hits       27791   27802     +11     
  Misses        49      49             

Impacted Files	Coverage Δ
...es/components/transformers/samplers/oversampler.py	100.0% <100.0%> (ø)
evalml/tests/component_tests/test_oversampler.py	100.0% <100.0%> (ø)

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[christopherbunn]

LGTM! Thanks for getting this in so quickly.

[bchen1116]

LGTM! Nice catch!