Fix import for infra test environment (#399)

typescript/infra/config/environments/test/index.ts

@@ -17,6 +17,7 @@ export const environment: CoreEnvironmentConfig<TestNetworks> = {
   // NOTE: Does not work from hardhat.config.ts
   getMultiProvider: async () => {
     const hre = await import('hardhat');
+    await import('@nomiclabs/hardhat-ethers');
     const [signer] = await hre.ethers.getSigners();
     return utils.getMultiProviderFromConfigAndSigner(testConfigs, signer);
   },