x, y, z, w values of HDR color are added to the timeline of Animation window when HDR color property is added via Mesh Renderer and the custom shader is used

How to reproduce:
1. Open the attached 'Curve.zip' project
2. Open 'SampleScene' Scene
3. Open Animation window
4. Create a new animation clip
5. Select Add Property -> Mesh Renderer -> Material._Color1
6. Expand the dropdown and notice there is x, y, z, w properties are added
7. Enter recording mode
8. Change Color1 HDR Color Property in the Inspector
9. Notice that r, g, b, a properties are added in the Animation Window

Expected result: r, g, b, a values are added to the timeline when HDR color selected via Mesh Renderer
Actual result: x, y, z, w values are added to the timeline when HDR color selected via Mesh Renderer

Reproducible with: 2018.4.15f1, 2020.1.0a18
Couldn't test: 2017.4.36f1 because HDR color is not introduced

Notes:
- Video of reproduction attached in Edit
- Reproducible with HDR color only
- Reproducible on macOS, Windows