feat: add cargo install fallback for dist prebuilt binary installation

[ChanTsune]

When a prebuilt binary installer is unavailable for the target architecture (e.g. riscv), the generated CI workflow now falls back to cargo install cargo-dist --locked --version <version> instead of failing outright.

resolve #2351

[mistydemeo]

I'm not sure if this is the right approach. This will catch any curl | sh failure, even ones that are unrelated to the installer being missing for a given architecture. I think it would make more sense to vary which install command we inject based on whether a binary should be available or not.