MTS candidate ordering if LFNST is used

[chollmann]

When using LFNST, the encoder evaluates the MTS candidates (DST7, DCT8) and (DCT8, DST7) in an order based on the intra mode:

IntraSearch.cpp line 2919

                | first        | second
intraMode <  34 | (DST7, DCT8) | (DCT8, DST7)
intraMode >= 34 | (DCT8, DST7) | (DST7, DCT8)

This is done if a bool variable moreProbMTSIdxFirst is true. This bool is set based on whether the transform index is larger than 1 (see EncCu.cpp line 1459). However, transform index = 1 (which is (DCT8, DST7)) is one of the modes that are supposed to be sorted.

The fix corrects the comparison to transform index > 0.

[ksuehring]

Merge request 589 was submitted to address the issue.

​https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/merge_requests/589

[XiangLi]

Fixed as suggested.