RenderSpriteToTexture2D required shaders get stripped when building player, with no way to include them

Steps to reproduce:

1. Make a script that uses `RenderSpriteToTexture2D`
2. Build player

Actual results: The `RenderSpriteToTexture2D` call fails and output a missing shader warning. This is because the builtin shaders to render the sprite are builtin and gets stripped from the player. The shaders under "Packages/com.unity.vectorgraphics/Runtime/Shaders" are ignored.

Expected results: The user is able to add the required shader in the "always included" section of the project properties.

 

Reproducible with versions: 6000.3 6000.4 6000.5 6000.6

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): 

Notes:

• https://discussions.unity.com/t/vector-graphics-preview-package/700495/1400