refactor: declaring `type` in hardhat.config.ts imports

hardhat.config.ts

@@ -1,7 +1,7 @@
 import "@nomicfoundation/hardhat-toolbox";
 import { config as dotenvConfig } from "dotenv";
-import { HardhatUserConfig } from "hardhat/config";
-import { NetworkUserConfig } from "hardhat/types";
+import type { HardhatUserConfig } from "hardhat/config";
+import type { NetworkUserConfig } from "hardhat/types";
 import { resolve } from "path";
 
 import "./tasks/accounts";