extension: Update to wasm32-wasip2 target (#30953)

Cleans things up now that wasm32-wasip2 is a supported target.

Before we merge, I will need to test against the current extensions to
make sure this is fine.

However, since our wit world isn't using any wasi package imports, this
shouldn't be a breaking change.

Release Notes:

- N/A

rust-toolchain.toml

@@ -7,6 +7,6 @@ targets = [
     "aarch64-apple-darwin",
     "x86_64-unknown-linux-gnu",
     "x86_64-pc-windows-msvc",
-    "wasm32-wasip1", # extensions
+    "wasm32-wasip2", # extensions
     "x86_64-unknown-linux-musl", # remote server
 ]