WASM: rename randomized_public_key to randomized_public_key_pair

This method returns a struct which also has a `randomized_public_key`
method, which results in code like this:

```rs
let r = x.randomized_public_key();
let p = r.randomized_public_key();
```

... which is very ambiguous/confusing. With this PR, the above code
becomes:

```rs
let r = x.randomized_public_key_pair();
let p = r.randomized_public_key();
```

Author: andiflabs

ironfish-rust-wasm/src/keys/view_keys.rs

@@ -150,7 +150,7 @@ impl ViewKey {
         self.0.nullifier_deriving_key.into()
     }
 
-    #[wasm_bindgen(js_name = randomizedPublicKey)]
+    #[wasm_bindgen(js_name = randomizedPublicKeyPair)]
     pub fn randomized_public_key_pair(&self) -> RandomizedPublicKeyPair {
         let (r, s) = self.0.randomized_public_key(thread_rng());
         RandomizedPublicKeyPair::new(r.into(), s.into())