WASM: Add try_clone implementations to Request and RequestBuilder (#1286)

Currently the wasm client does not implement `try_clone` on `Request` or `RequestBuilder` like the blocking and async clients.

This PR adds infallible `try_clone` implementations to the wasm client to improve the API parity.

*Note*: Even though these APIs are infallible on wasm (no streaming bodies), I chose to keep the API identical.

src/wasm/body.rs

@@ -17,6 +17,7 @@ pub struct Body {
     inner: Inner,
 }
 
+#[derive(Clone)]
 enum Inner {
     Bytes(Bytes),
     #[cfg(feature = "multipart")]
@@ -56,6 +57,12 @@ impl Body {
             Inner::Multipart(form) => form.is_empty(),
         }
     }
+
+    pub(crate) fn clone(&self) -> Body {
+        Self {
+            inner: self.inner.clone(),
+        }
+    }
 }
 
 impl From<Bytes> for Body {