fix: adjust to failing bigint initializer in new version, that does not default to 0 when initializing from empty string

Author: mdab121

web3swift/src/Extensions/HexExtensions.swift

@@ -8,7 +8,7 @@ import Foundation
 
 public extension BigUInt {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix.lowercased(), radix: 16)
+        self.init(hex.web3.noHexPrefix.web3.orZero.lowercased(), radix: 16)
     }
 }
 
@@ -24,7 +24,7 @@ public extension Web3Extensions where Base == BigUInt {
 
 public extension BigInt {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix.lowercased(), radix: 16)
+        self.init(hex.web3.noHexPrefix.web3.orZero.lowercased(), radix: 16)
     }
 }
 
@@ -79,6 +79,11 @@ public extension Web3Extensions where Base == String {
         return base
     }
 
+    var orZero: String {
+        if base.isEmpty { return "0" }
+        return base
+    }
+
     var stringValue: String {
         if let byteArray = try? HexUtil.byteArray(fromHex: base.web3.noHexPrefix), let str = String(bytes: byteArray, encoding: .utf8) {
             return str