feat: add addAccountEmailRecord mutation and corresponding integration

[willopez]

Resolves #5643
Impact: minor
Type: feature

Issue

There was no GraphQL mutation to add an email to a user's account

Solution

Add addAccountEmailRecord mutation and corresponding integration test.

mutation {
  addAccountEmailRecord(input: {
    accountId: "cmVhY3Rpb24vYWNjb3VudDpOR242R1I4TDdEZlduZkdDaA==",
    email: "[email protected]"
  }){
    account {
      emailRecords {
        address
        provides
        verified
      }
    }
  }
}

Testing

1. Add a new email to an existing account by executing the mutation above
2. Verify new email was added correctly

[willopez]

@mikemurray ready for another review

[mikemurray]

👍