Hotfix: Prevent ZMQ-based bitcoin wallet to panic (ark-network#383)

* Hotfix bct embedded wallet w/ ZMQ

* Fixes

server/internal/infrastructure/wallet/btc-embedded/wallet.go

@@ -226,7 +226,7 @@ func WithPollingBitcoind(host, user, pass string) WalletOption {
 				User: bitcoindConfig.User,
 				Pass: bitcoindConfig.Pass,
 			},
-			"CONSERVATIVE",
+			"ECONOMICAL",
 			chainfee.AbsoluteFeePerKwFloor,
 		)
 		if err != nil {
@@ -298,6 +298,27 @@ func WithBitcoindZMQ(block, tx string, host, user, pass string) WalletOption {
 			time.Sleep(1 * time.Second)
 		}
 
+		estimator, err := chainfee.NewBitcoindEstimator(
+			rpcclient.ConnConfig{
+				Host: bitcoindConfig.Host,
+				User: bitcoindConfig.User,
+				Pass: bitcoindConfig.Pass,
+			},
+			"ECONOMICAL",
+			chainfee.AbsoluteFeePerKwFloor,
+		)
+		if err != nil {
+			return fmt.Errorf("failed to create bitcoind fee estimator: %w", err)
+		}
+
+		if err := withExtraAPI(&bitcoindRPCClient{chainClient})(s); err != nil {
+			return err
+		}
+
+		if err := withFeeEstimator(estimator)(s); err != nil {
+			return err
+		}
+
 		if err := withChainSource(chainClient)(s); err != nil {
 			chainClient.Stop()
 			bitcoindConn.Stop()