Re-enable downgrade tests after PrecompileTools minimum version update

## Summary The downgrade tests have been temporarily disabled in the Downgrade.yml workflow because they fail when dependencies are downgraded to their minimum compatible versions. ## Issue When Julia downgrades `PrecompileTools` to v1.0.0 (the minimum compatible version), the package fails to load with the error: ``` ERROR: LoadError: UndefVarError: `PrecompileTools` not defined ``` This appears to be an issue with PrecompileTools v1.0.0 not being fully compatible with the current codebase. ## Solution Options 1. Bump the minimum `PrecompileTools` version in the compat section to a version that works correctly 2. Wait for an upstream fix in PrecompileTools ## Related - Disabled in PR that splits JET tests to separate workflow - Similar to [DelayDiffEq.jl#356](https://github.com/SciML/DelayDiffEq.jl/issues/356)