solana/token_bridge: add custody_signer derive to wasm

Change-Id: I9dc9e5d80dce3e580257877b4640df3408b4b568

solana/modules/token_bridge/program/src/wasm.rs

@@ -1,6 +1,7 @@
 use crate::{
     accounts::{
         AuthoritySigner,
+        CustodySigner,
         EmitterAccount,
         WrappedDerivationData,
         WrappedMetaDerivationData,
@@ -391,6 +392,14 @@ pub fn emitter_address(program_id: String) -> Vec<u8> {
     emitter.to_bytes().to_vec()
 }
 
+#[wasm_bindgen]
+pub fn custody_signer(program_id: String) -> Vec<u8> {
+    let program_id = Pubkey::from_str(program_id.as_str()).unwrap();
+    let custody_signer = CustodySigner::key(None, &program_id);
+
+    custody_signer.to_bytes().to_vec()
+}
+
 #[wasm_bindgen]
 pub fn approval_authority_address(program_id: String) -> Vec<u8> {
     let program_id = Pubkey::from_str(program_id.as_str()).unwrap();