Jpeg sampling factor validation #1894

[br3aker]

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Description

Closes #1894. Moved mentioned image from decoder tests to 'throws exception' tests.

[codecov]

Codecov Report

Merging #1899 (791a1a1) into master (a356848) will decrease coverage by 0%.
The diff coverage is 83%.

@@          Coverage Diff           @@
##           master   #1899   +/-   ##
======================================
- Coverage      87%     87%   -1%     
======================================
  Files         960     960           
  Lines       50975   50979    +4     
  Branches     6311    6312    +1     
======================================
+ Hits        44733   44736    +3     
  Misses       5202    5202           
- Partials     1040    1041    +1     

Flag	Coverage Δ
unittests	87% <83%> (-1%)	⬇️

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

Impacted Files	Coverage Δ
...p/Formats/Jpeg/Components/Decoder/JpegComponent.cs	93% <ø> (-1%)	⬇️
src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs	89% <80%> (-1%)	⬇️
src/ImageSharp/Common/Helpers/Numerics.cs	97% <100%> (+<1%)	⬆️
src/ImageSharp/Formats/Jpeg/JpegThrowHelper.cs	60% <100%> (+5%)	⬆️

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[antonfirsov]

Looks good, thanks!