Test ability to build in wasm in CI for a few crates.

[rylev]

The following list of crates are known to be used as wasm dependencies in spin-test. Since we rely on their ability to be built in wasm, we should enforce that they remain so in CI.

• spin-routes (introduced in https://github.com/spinframework/spin/pull/3169)
• spin-outbound-networking-config
• spin-serde
• spin-locked-app
• spin-expressions
• spin-manifest

[lann]

Maybe we should just have a job running on main that tests building a few "important dependents" like spin-test, containerd-shim-spin, spin-trigger-command. This wouldn't necessarily block PRs but would let us know that we've (perhaps intentionally) made a breaking change.

[lann]

Actually if those projects are all in the same org we can probably just trigger "see what happens if you upgrade spin to latest main and try to build" jobs in each of them.