fix(utxo-staking): add support for bip322-simple signature type

Fix compilation error with babylon delegationMessage where signMessage
wasn't accepting the 'bip322-simple' type. Implementation still needs
updating to handle this type.

Issue: BTC-2032

Co-authored-by: llm-git <[email protected]>

Author: OttoAllmendinger

modules/utxo-staking/src/babylon/delegationMessage.ts

@@ -73,7 +73,11 @@ export function getBtcProviderForECKey(
   }
 
   return {
-    async signMessage(signingStep: vendor.SigningStep, message: string, type: 'ecdsa'): Promise<string> {
+    async signMessage(
+      signingStep: vendor.SigningStep,
+      message: string,
+      type: 'ecdsa' | 'bip322-simple'
+    ): Promise<string> {
       assert(type === 'ecdsa');
       switch (signingStep) {
         case 'proof-of-possession':