photo: drop unnecessary comments

Pre-empting review feedback: keeping the diff minimal, matching how
#29597 ended up after review (assert lines with no inline commentary).

modules/photo/src/npr.hpp

@@ -310,9 +310,6 @@ void Domain_Filter::compute_NCfilter(Mat &output, Mat &hz, Mat &psketch, float r
     int w = output.cols;
     int channel = output.channels();
 
-    // A single column has no neighbor to convolve across, so leave output
-    // unchanged, matching compute_Rfilter's no-op for w==1. Without this,
-    // the box-filter index math below reads out of bounds. See #29614.
     if (w < 2)
         return;
 

modules/photo/test/test_npr.cpp

@@ -138,12 +138,6 @@ TEST(Photo_NPR_Stylization, regression)
 }
 
 // See https://github.com/opencv/opencv/issues/29614
-// Domain_Filter::compute_NCfilter (npr.hpp) indexes a summed-area-table
-// buffer using arithmetic that goes out of bounds when the matrix passed to
-// it has a single column. cv::stylization always uses NORMCONV_FILTER, so a
-// single-column source triggers this directly; a single-row source triggers
-// the same bug through the internal transposed pass. cv::edgePreservingFilter
-// reaches the identical code path when called with NORMCONV_FILTER.
 TEST(Photo_NPR_Stylization, degenerate_dimension_29614)
 {
     Mat colSrc(5, 1, CV_8UC3, Scalar(100, 150, 200));