How to know if a field is encrypted in mongodb?

Question

I have a requirement to implement client side field level encryption, and I implemented it using the Automatic Encryption provided by MongoDB, now I have to update the schema of an existing collection and need to encrypt the existing data in the field, for that I need to find weather the field is encrypted or not, how can I achieve it.

This is my schema

{
  $jsonSchema: {
    bsonType: 'object',
    properties: {
      title: {
        bsonType: 'string'
      },
      author: {
        bsonType: 'string'
      },
      category: {
        bsonType: 'string'
      },
      name: {
        encrypt: {
          bsonType: 'string',
          keyId: [
            {
              $binary: {
                base64: 'pDxBjDM2RcKbaDugcRHvPg==',
                subType: '04'
              }
            }
          ],
          algorithm: 'AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic'
        }
      }
    }
  }
}

I am unable to find any lead, as I am a beginner to MongoDB.