VFX shader dependencies can be assigned to Mesh Output

How to reproduce:

1. Open the attached package
2. Open Mesh Output VFX
3. Open Shader Object Picker
4. Notice that VFX are in the search results
5. Assign any vfx to teh shader graph field

Expected result: VFXs are not listed in the search, and shader depenedencies cannot be assigned

Actual result: Errors are thrown to the console, VFXs are listed and can be assigned to the field

Not reproducible with: 2021.3.11f1

Error message: [Worker39] Shader error in 'Hidden/VFX/LitOutputs - Simple Lit Translucent - Cookie/System (1)/Output Particle HDRP Lit Cube': unrecognized identifier 'OUTPUT_GBUFFER' at line 2560 (on d3d11)

Scenario: sometimes it catches SG and then assigns that shader to several mesh outputs