Remove hardcoded subsampling.

[JimBobSquarePants]

Prerequisites

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• I have provided test coverage for my change (where applicable)

Description

Remove the hardcoded subsampling initializer from JpegComponent. Our decoder can handle the interleaved for CMYK and YccK jpegs. Fix #817

[codecov]

Codecov Report

Merging #834 into master will decrease coverage by 0.09%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #834     +/-   ##
=========================================
- Coverage   88.84%   88.75%   -0.1%     
=========================================
  Files        1015     1015             
  Lines       44167    44165      -2     
  Branches     3181     3180      -1     
=========================================
- Hits        39241    39199     -42     
- Misses       4201     4206      +5     
- Partials      725      760     +35

Impacted Files	Coverage Δ
...Sharp.Tests/Formats/Jpg/JpegDecoderTests.Images.cs	100% <100%> (ø)	⬆️
...p/Formats/Jpeg/Components/Decoder/JpegComponent.cs	97.61% <100%> (-0.16%)	⬇️
tests/ImageSharp.Tests/TestImages.cs	100% <100%> (ø)	⬆️
...xelFormats/PixelOperations{TPixel}.PixelBenders.cs	89.34% <0%> (-9.84%)	⬇️
...Processing/Processors/Transforms/TransformUtils.cs	88.29% <0%> (-5.32%)	⬇️
src/ImageSharp/Common/Helpers/ImageMaths.cs	82.05% <0%> (-5.13%)	⬇️
.../Processing/Processors/Transforms/CropProcessor.cs	96% <0%> (-4%)	⬇️
...ocessing/Processors/Dithering/ErrorDiffuserBase.cs	93.75% <0%> (-3.13%)	⬇️
...rs/Normalization/HistogramEqualizationProcessor.cs	97.5% <0%> (-2.5%)	⬇️
...eSharp.Tests/IO/DoubleBufferedStreamReaderTests.cs	97.61% <0%> (-2.39%)	⬇️
... and 15 more

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[codecov]

Codecov Report

Merging #834 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #834      +/-   ##
==========================================
- Coverage   88.84%   88.84%   -0.01%     
==========================================
  Files        1015     1015              
  Lines       44169    44167       -2     
  Branches     3181     3180       -1     
==========================================
- Hits        39243    39241       -2     
  Misses       4201     4201              
  Partials      725      725

Impacted Files	Coverage Δ
...Sharp.Tests/Formats/Jpg/JpegDecoderTests.Images.cs	100% <100%> (ø)	⬆️
...p/Formats/Jpeg/Components/Decoder/JpegComponent.cs	97.61% <100%> (-0.16%)	⬇️
tests/ImageSharp.Tests/TestImages.cs	100% <100%> (ø)	⬆️

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[JimBobSquarePants]

I'm gonna go ahead and merge this. Coverage is 100% and all tests pass.