Don't publish boa_wasm to npm if version exists

[jasonwilliams]

We sometimes need to re-publish the same release which means publishing the same version. Cargo will ignore publishing a crate if it already exists but npm still fails.

It would be nice to have npm not fail if the version was already uploaded to the registry

our workflow lives here:
https://github.com/boa-dev/boa/blob/main/.github/workflows/release.yml#L39-L70

I guess we would want a step that runs npm view @boa-dev/boa_wasm version then checks the value against the current version (from Cargo.toml) if they match exit the workflow without any errors