Post Process Materials do not appear in Sequencer

When Having a SkeletalMesh or Static Mesh, you can control Material Parameters directly. Something like that is missing for Post Process Materials.

Matinee had a generic Float or Vector Track.If Sequencer had these kinds of Tracks as well it would make things a bit easier. Level Sequences have a Director Object, someone could drive Post Process Materials with that.

This was reported and tested in 4.21.2 (CL-4753647), This was reproduced in 4.22.2 (CL-6574378), 4.23 (CL-7021509), and Main 4.24 (CL-7039453)

1. Open the UE4 Editor and create a Blank Project
2. Create a Level Sequence
3. Click the button to "Create a new camera and set it as the current camera cut"
4. Go to Details Settings of the Camera. Under Post Processing->Rendering Features -> Post Process Materials add a Post Process Material that has Parameters
5. In Sequencer under the Camera Component, add a Track Post Process Settings -> Post Process Materials[0] -> Post Process Materials

Results: There is only a Weight[0] track which controls the Post Process Weight.

Expected: Tracks for every Parameter in the Post Process Material