Mismatch between colr information and bitstream information should be avoided

[cconcolato]

To facilitate conformance of ISOBMFF regarding the colr box, the spec should be updated to include a SHOULD indicating that mismatches between colr information and bitstream information should be avoided.

If colour information is supplied in both this box, and also in the video bitstream, this box takes precedence, and over-rides the information in the bitstream.

to:

The colour information supplied in both this box and in the video bitstream SHOULD match. If it is not the case, this box takes precedence, and over-rides the information in the bitstream.

This came up in ComplianceWarden/AVIF discussions: gpac/ComplianceWarden#36 (comment)