findOutline4 function does not check itself for nonMaskValue

https://github.com/facebookresearch/ocean/blob/3c24ca74a826ae3273f3eb4294b0e071e906318a/impl/ocean/cv/segmentation/MaskAnalyzer.cpp#L306

The output for this function is described as this:

> Resulting outline-4 pixels, **the pixel itself is not a mask pixel** but has at least one neighbor mask pixel in the four-neighborhood

But nowhere does it ensure that the pixel being analyzed is not a mask pixel. As a result the output contains all of the mask pixels in addition to the outline pixels. See Line 381 for example:

`if (maskRow[x - 1u] != nonMaskValue || maskRow[x + 1u] != nonMaskValue || maskRowBottom[x] != nonMaskValue)`

It is done correctly in other functions, such as here in Line 1784:

`if (row1[x] != nonMaskValue && (row1[x - 1u] == nonMaskValue || row1[x + 1u] == nonMaskValue || row0[x] == nonMaskValue || row2[x] == nonMaskValue))`