feat(abstract-utxo): move RootWalletKeys type to utxo-lib

Move RootWalletKeys type definition to utxo-lib from abstractUtxoCoin
to better organize code structure and eliminate circular dependencies.

Issue: BTC-2806

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

Author: OttoAllmendinger

modules/abstract-utxo/src/transaction/fixedScript/signTransaction.ts

@@ -6,10 +6,12 @@ import { bitgo } from '@bitgo/utxo-lib';
 import * as utxolib from '@bitgo/utxo-lib';
 import { isTriple, Triple } from '@bitgo/sdk-core';
 
-import { AbstractUtxoCoin, DecodedTransaction, RootWalletKeys } from '../../abstractUtxoCoin';
+import { AbstractUtxoCoin, DecodedTransaction } from '../../abstractUtxoCoin';
 
 import { signAndVerifyPsbt, signAndVerifyWalletTransaction } from './sign';
 
+type RootWalletKeys = bitgo.RootWalletKeys;
+
 /**
  * Key Value: Unsigned tx id => PSBT
  * It is used to cache PSBTs with taproot key path (MuSig2) inputs during external express signer is activated.