Update email code to send an email per EditUserCell

using multiple recipients is break of privacy since user will be able
to see each other's emails.

app/web/src/components/EditUserCell/EditUserCell.js

@@ -5,7 +5,7 @@ import { navigate, routes } from '@redwoodjs/router'
 import UserProfile from 'src/components/UserProfile'
 
 export const QUERY = gql`
-  query FIND_USER_BY_ID($userName: String!) {
+  query FIND_USER_BY_USERNAME($userName: String!) {
     user: userName(userName: $userName) {
       id
       userName