chores: added assetchain-testnet in chains folder (#4445)

Author: KodeSage

packages/thirdweb/src/chains/chain-definitions/assetchain-testnet.ts

@@ -0,0 +1,22 @@
+import { defineChain } from "../utils.js";
+
+/**
+ * @chain
+ */
+export const assetChainTestnet = /* @__PURE__ */ defineChain({
+  id: 42421,
+  name: "AssetChain Testnet",
+  nativeCurrency: {
+    name: "Real World Asset",
+    symbol: "RWA",
+    decimals: 18,
+  },
+  blockExplorers: [
+    {
+      name: "Asset Chain Testnet Explorer",
+      url: "https://scan-testnet.assetchain.org",
+      apiUrl: "https://scan-testnet.assetchain.org/api",
+    },
+  ],
+  testnet: true,
+});