fix(firestore-send-email): require fs inline in clean script

Author: inlined

firestore-send-email/functions/package.json

@@ -6,7 +6,7 @@
     "prepare": "npm run build",
     "build": "npm run clean && npm run compile",
     "build:watch": "npm run clean && tsc --watch",
-    "clean": "node -e \"fs.rmSync('lib', { recursive: true, force: true })\"",
+    "clean": "node -e \"require('fs').rmSync('lib', { recursive: true, force: true })\"",
     "compile": "tsc",
     "local:emulator": "cd ../../_emulator && firebase emulators:start -P demo-test",
     "test": "cd ../../_emulator && firebase emulators:exec --only extensions jest -P demo-test",