title: Firestore: How to query data from a map of an array
body: <p>Here is the schema for test db: 
  <a href="https://i.stack.imgur.com/Pd4iR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Pd4iR.png" alt="enter image description here"></a></p>
  
  <p>I want to write a query that can get all the documents where contacts have id=1 in any of the array index. </p>
  
  <p>I have checked <code>array_contains</code> operator for firestore but the thing is my array have map which then have field id. </p>
  
  <p>Thanks</p>