Ignoring trigger because the Cloud Firestore emulator is not running (firebase serve)

### How to reproduce these conditions

**Sample name or URL where you found the bug**
https://github.com/firebase/functions-samples/tree/master/stripe

**Failing Function code used (including require/import commands at the top)**
'use strict';

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const logging = require('@google-cloud/logging')();
const stripe = require('stripe')(functions.config().stripe.token);
const currency = functions.config().stripe.currency || 'USD';

// [START chargecustomer]
// Charge the Stripe customer whenever an amount is written to the Realtime database
exports.createStripeCharge = functions.firestore.document('stripe_customers/{userId}/charges/{id}').onCreate(async (snap, context) => {
const val = snap.data();
try {
// Look up the Stripe customer id written in createStripeCustomer
const snapshot = await admin.firestore().collection(`stripe_customers`).doc(context.params.userId).get()
const snapval = snapshot.data();
const customer = snapval.customer_id
// Create a charge using the pushId as the idempotency key
// protecting against double charges
const amount = val.amount;
const idempotencyKey = context.params.id;
const charge = {amount, currency, customer};
if (val.source !== null) {
charge.source = val.source;
}
const response = await stripe.charges.create(charge, {idempotency_key: idempotencyKey});
// If the result is successful, write it back to the database
return snap.ref.set(response, { merge: true });
} catch(error) {
// We want to capture errors and render them in a user-friendly way, while
// still logging an exception with StackDriver
console.log(error);
await snap.ref.set({error: userFacingMessage(error)}, { merge: true });
return reportError(error, {user: context.params.userId});
}
});
// [END chargecustomer]]

// When a user is created, register them with Stripe
exports.createStripeCustomer = functions.auth.user().onCreate(async (user) => {
const customer = await stripe.customers.create({email: user.email});
return admin.firestore().collection('stripe_customers').doc(user.uid).set({customer_id: customer.id});
});

// Add a payment source (card) for a user by writing a stripe payment source token to Realtime database
exports.addPaymentSource = functions.firestore.document('/stripe_customers/{userId}/tokens/{pushId}').onCreate(async (snap, context) => {
const source = snap.data();
const token = source.token;
if (source === null){
return null;
}

try {
const snapshot = await admin.firestore().collection('stripe_customers').doc(context.params.userId).get();
const customer = snapshot.data().customer_id;
const response = await stripe.customers.createSource(customer, {source: token});
return admin.firestore().collection('stripe_customers').doc(context.params.userId).collection("sources").doc(response.fingerprint).set(response, {merge: true});
} catch (error) {
await snap.ref.set({'error':userFacingMessage(error)},{merge:true});
return reportError(error, {user: context.params.userId});
}
});

// When a user deletes their account, clean up after them
exports.cleanupUser = functions.auth.user().onDelete(async (user) => {
const snapshot = await admin.firestore().collection('stripe_customers').doc(user.uid).get();
const customer = snapshot.data();
await stripe.customers.del(customer.customer_id);
return admin.firestore().collection('stripe_customers').doc(user.uid).delete();
});

// To keep on top of errors, we should raise a verbose error report with Stackdriver rather
// than simply relying on console.error. This will calculate users affected + send you email
// alerts, if you've opted into receiving them.
// [START reporterror]
function reportError(err, context = {}) {
// This is the name of the StackDriver log stream that will receive the log
// entry. This name can be any valid log stream name, but must contain "err"
// in order for the error to be picked up by StackDriver Error Reporting.
const logName = 'errors';
const log = logging.log(logName);

// https://cloud.google.com/logging/docs/api/ref_v2beta1/rest/v2beta1/MonitoredResource
const metadata = {
resource: {
type: 'cloud_function',
labels: {function_name: process.env.FUNCTION_NAME},
},
};

// https://cloud.google.com/error-reporting/reference/rest/v1beta1/ErrorEvent
const errorEvent = {
message: err.stack,
serviceContext: {
service: process.env.FUNCTION_NAME,
resourceType: 'cloud_function',
},
context: context,
};

// Write the error log entry
return new Promise((resolve, reject) => {
log.write(log.entry(metadata, errorEvent), (error) => {
if (error) {
return reject(error);
}
return resolve();
});
});
}
// [END reporterror]

// Sanitize the error message for the user
function userFacingMessage(error) {
return error.type ? error.message : 'An error occurred, developers have been alerted';
}
**Steps to set up and reproduce**
Windows 10, brand new installation of node 10 and firebase-tools (v 6.9.2).
Follow the instructions on the github page for installing the npm package and setting up stripe key and so on, but instead of firebase deploy, I used firebase serve.
Change node version to 10 in package.json.
Attached stripe example to firebase hosting as well.

**Sample data pasted or attached as JSON (not an image)**

**Security rules used**

### Debug output

**Errors in the [console logs](https://console.firebase.google.com/project/_/functions/logs?search=&severity=DEBUG)**
functions: Using node@10 from host.
+ functions: Emulator started at http://localhost:5001
i functions: Watching "" for Cloud Functions...
i hosting: Serving hosting files from: public
+ hosting: Local server: http://localhost:5000
! Default "firebase-admin" instance created!
! Ignoring trigger "createStripeCharge" because the Cloud Firestore emulator is not running.
! Ignoring trigger "createStripeCustomer" because the Cloud Firestore emulator is not running.
! Ignoring trigger "addPaymentSource" because the Cloud Firestore emulator is not running.
! Ignoring trigger "cleanupUser" because the service "firebaseauth.googleapis.com" is not yet supported.
> (node:23520) DeprecationWarning: grpc.load: Use the @grpc/proto-loader module with grpc.loadPackageDefinition instead

**Screenshots**

### Expected behavior
The local emulator starts running and I can test firebase functions without deploying them.

### Actual behavior
Firebase hosting works fine, but all cloud firestore functions get ignored.