SDK / exoplayer

Use the PQ OETF and EOTF to ensure that intermediate fragment shader operations
using PQ are in linear BT.2020 rather than PQ and HLG-1 BT.2020.

Also, swap the OETF and EOTF in shaders, as they were used incorrectly before

Manually tested by verifying transformer demo HLG and PQ videos look the same with and without this CL, including with a BitmapOverlayProcessor enabled to test flows both with one MatrixTransformationProcessor that skips HDR TFs, and with one that doesn't.

PiperOrigin-RevId: 469736067