feat(abstract-utxo): use coin name to get family

Replace getFamilyFromNetwork with getMainnetCoinName to directly
determine the family name from the coin name without going through
the network.

Issue: BTC-2909

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

modules/abstract-utxo/src/abstractUtxoCoin.ts

@@ -77,8 +77,8 @@ import {
 } from './transaction/descriptor/verifyTransaction';
 import { assertDescriptorWalletAddress, getDescriptorMapFromWallet, isDescriptorWallet } from './descriptor';
 import {
-  getFamilyFromNetwork,
   getFullNameFromNetwork,
+  getMainnetCoinName,
   getNetworkFromCoinName,
   UtxoCoinName,
   UtxoCoinNameMainnet,
@@ -397,7 +397,7 @@ export abstract class AbstractUtxoCoin
   }
 
   getFamily(): UtxoCoinNameMainnet {
-    return getFamilyFromNetwork(this.network);
+    return getMainnetCoinName(this.name);
   }
 
   getFullName(): string {