fix: broken hardhat-gas-reporter due to empty string in config

see https://github.com/cgewecke/hardhat-gas-reporter/issues/59#issuecomment-812589987

hardhat.config.ts

@@ -58,7 +58,7 @@ const config: HardhatUserConfig = {
   gasReporter: {
     currency: "USD",
     enabled: process.env.REPORT_GAS ? true : false,
-    excludeContracts: [""],
+    excludeContracts: [],
     src: "./contracts",
   },
   networks: {