Since matrices are usually indexed **row first**, displaying matrices in
the UI seems flipped.
They are stored as flat arrays.
When `matrix[1][0]` is accessed via python, the logic from
`pyrna_py_from_array_index` will actually look up index 2 in the flat
array (rightfully so).
But UI code was flipped in that regard.
The second value in the flat array **should** show at row 1 column 0,
but it currently doesnt.
Now (hopefully) handled properly (not only in `ui_item_array` but also
made code in `ui_item_rna_size` detect proper row count for a `height`)
Pull Request: https://projects.blender.org/blender/blender/pulls/148197