generated dataconnect.yaml schema has invalid `schemas` property - `fdcwebhooks` experiment enabled

[aalej]

[REQUIRED] Environment info

firebase-tools: v15.22.4
Firebase SQL Connect for VSCode: v2.4.1

Platform: macOS

[REQUIRED] Test case

N/A

[REQUIRED] Steps to reproduce

1. Run firebase experiments:enable fdcwebhooks.
   • This is enabled by default

     firebase-tools/src/experiments.ts

     Lines 202 to 206 in 0038038

     	fdcwebhooks: {
     	shortDescription: "Enable Firebase SQL Connect webhooks feature.",
     	default: true,
     	public: false,
     	},

2. Run firebase init dataconnect --project demo-project

firebase init dataconnect --project demo-project

$ firebase init dataconnect --project demo-project

     ######## #### ########  ######## ########     ###     ######  ########
     ##        ##  ##     ## ##       ##     ##  ##   ##  ##       ##
     ######    ##  ########  ######   ########  #########  ######  ######
     ##        ##  ##    ##  ##       ##     ## ##     ##       ## ##
     ##       #### ##     ## ######## ########  ##     ##  ######  ########

You're about to initialize a Firebase project in this directory:

  /Users/PATH/reports/dataconnect-yaml-schema-1


=== Project Setup

First, let's associate this project directory with a Firebase project.
You can create multiple project aliases by running firebase use --add, 

Skipping Firebase project setup because a demo project is provided

=== Dataconnect Setup
⚠  dataconnect: Cannot detect an existing app in the current directory.
✔ Do you want to create an app template? skip
✔  Wrote dataconnect/dataconnect.yaml
✔  Wrote dataconnect/seed_data.gql
✔  Wrote dataconnect/schema/schema.gql
✔  Wrote dataconnect/example/connector.yaml
✔  Wrote dataconnect/example/queries.gql
✔  Wrote dataconnect/example/mutations.gql
i  dataconnect: No apps to setup SQL Connect Generated SDKs

=== Agent Skills Setup
If you are using an AI coding agent, Firebase Agent Skills make it an expert at Firebase.
✔ Would you like to install agent skills for Firebase? No

✔  Wrote configuration info to firebase.json
✔  Wrote project information to .firebaserc
✔  Wrote .gitignore

✔  Firebase initialization complete!

To get started:

i  Install the SQL Connect VS Code Extensions. You can explore SQL Connect Query on local pgLite and Cloud SQL Postgres Instance.

[REQUIRED] Expected behavior

There should be no errors in the generated dataconnect.yaml file

[REQUIRED] Actual behavior

Notes

we might need to update the dataconnect-yaml.json to support a schemas property in

firebase-tools/schema/dataconnect-yaml.json

Lines 81 to 83 in 0038038

	"schema": {
	"$ref": "#/definitions/schema"
	}