chore: switch from wasm32-unknown-unknown to wasm32-wasip1

[greenhat]

As a workaround for our old rustc version (fails in fib tests). See rust-lang/libm#214 (comment)
Besides, that I think we should stick to wasm32-wasi everywhere.

[greenhat]

@bitwalker Although I stacked this PR on the #372, the merging order is not important here.

[bitwalker]

I didn't need to make this change to get our build working, I think only the old wasm32-wasi target was removed, so that was causing tests to fail, but removing that target via rustup was sufficient to get things working again (although I combined it with an update of the stable/nightly toolchains, so there may be some fixes I picked up that I am not aware of).

I think we should continue to use wasm32-unknown-unknown for tests which are not Component Model based, since it is technically the appropriate target for pure Rust projects that don't target the rollup, and it doesn't hurt to have a check on any unintentional assumptions we make due to the nature of wasm32-wasip1 or wasm32-wasip2 targets.

Given that, I'm going to close this for now I think, if you disagree, feel free to reopen and let's discuss further.