Reenable Apple VisionOS CI

Currently broken:

```
  error: building std is not supported on the following targets: aarch64-apple-visionos
  error: process didn't exit successfully: `/home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo check -Z build-std=std,panic_abort --target aarch64-apple-visionos --manifest-path Cargo.toml --no-default-features` (exit status: 101)
```