add check to raw feature filter for removing all features

[crupley]

Related issues
Raw Feature Filter should throw exception when removing all features #302

Describe the proposed solution
Throw an exception when raw feature filter removes all features

Describe alternatives you've considered
In linked issue

Additional context
None

[codecov]

Codecov Report

Merging #303 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #303      +/-   ##
=========================================
- Coverage   86.42%   86.4%   -0.02%     
=========================================
  Files         322     322              
  Lines       10570   10572       +2     
  Branches      350     566     +216     
=========================================
  Hits         9135    9135              
- Misses       1435    1437       +2

Impacted Files	Coverage Δ
...a/com/salesforce/op/filters/RawFeatureFilter.scala	92.93% <100%> (+0.07%)	⬆️
...es/src/main/scala/com/salesforce/op/OpParams.scala	85.71% <0%> (-4.09%)	⬇️

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[gerashegalov]

LGTM

[leahmcguire]

LGTM