Mailgun Rate Limiter [possibly] hit

### 👟 Reproduction steps After you've previously setup Mailgun as a Messaging Provider; 1. Go to AW Cloud 3. Click on Messaging 4. Create an email to many (30+) email targets/recipients 5. Send the email now (or at another time) Appwrite (AW) will show that the email has been sent to all recipients, while Mailgun (MG) logs will show that only 20-25 requests to send an email were logged. Originally raised at https://discord.com/channels/564160730845151244/1406618445491212389 and refined in https://discord.com/channels/564160730845151244/1406618445491212389/1454088484900966533 & https://discord.com/channels/564160730845151244/1406618445491212389/1454282386282905743 > It would appear that either AW isn't sending all the requests [individually] to send an email, or Mailgun is dropping them (maybe some type of API rate limiting). > Is their logging on the AW Cloud side to show when the requests to Mailgun fail? Is AW using the best API to batch send an email with multiple recipients to Mailgun? (it would appear to me that AW is looping the API calls/hammering the Mailgun endpoint servers). ### 👍 Expected behavior - email request passed to MG in one API call - request status shown in AW UI When MG is setup in the AW web UI with an API key, I'd expect that the API is being used (not SMTP), as such the API allows for an array of recipients to be specified. #### Possible pointers for Contributors From a quick search of the codebase, it would seem that changes would need to be made in these to files to be able to handle recipients as an array when using a service provider (not SMTP). - https://github.com/appwrite/appwrite/blob/b03aa8d6322db25dfd9e8840f23bc210f6c22d9d/src/Appwrite/Event/Mail.php#L9 - https://github.com/appwrite/appwrite/blob/44ec8de6bf26792c5538a27bf4be88da98af112f/src/Appwrite/Platform/Workers/Mails.php#L76 Information about MG rate limiting responses: https://discord.com/channels/564160730845151244/1406618445491212389/1454295163525529651 ### 🎲 Appwrite…