Update SWC relay Wasm plugin (#8218)
### Description
Fixes https://github.com/vercel/next.js/issues/64890
When `eagerEsModule` is used, the SWC relay plugin _prepends_ the import statements, and it made server actions transform think `"use server"` is not the first statement.
### Testing Instructions
I added tests to https://github.com/swc-project/plugins/pull/306
