[BUG] RPC Method Proxy Issues: Export and Usability

RPC methods are being proxied, which makes usage difficult. In the index.d.ts file, export is specified, but the generated index.js exports a Proxy. This also causes a "not found" error, similar to the example. RPC methods should be moved outside the proxy.

https://github.com/cloudflare/workers-rs/blob/490c6c9082e06db5e29a6d622f37893628191396/worker-build/src/js/shim.js#L113

lib.rs:
```rust
#[wasm_bindgen]
pub async fn greet()
```
build/index.d.ts:
```ts
export function greet(): void;
```
demo.ts:
```ts
import {greet} from "./build/index.js" //throw error not found greet
```