Error while processing shader in mainline bevy

[Shfty]

When using regular v0.9.1 instead of Shfty/bevy:early-shader-defs, Shaders fail to process - preventing their material from rendering - and print the following error:

ERROR bevy_render::render_resource::pipeline_cache: failed to process shader: This Shader's format does not support processing shader defs.

Upstream issue: bevy/#7771

[Shfty]

A fix has been merged into bevy main, so this is no longer a blocker.

However, bevyengine/bevy#7903 remains underway, which is a nicer solution to the problem, and the one currently depended on by bevy-rust-gpu - will continue to work on it and close this issue once it's merged.

[Shfty]

Closing this in lieu of a new issue specific to the need for shader def access.