Change Promise.all to Promise.allSettle for ease of error handling

[satasuk03]

sendgrid-nodejs/packages/mail/src/classes/mail-service.js

Line 165 in 07b4f71

const promise = Promise.all(data.map(item => {

In this case, if we send 100 mails at a time, but if a single mail is failed, all pending mails will be stopped.
In the other hand, it should send as much as possible and return the send result to the user (cb signature also need to be updated)