404's when fetching .eml files (from Action Mailbox)

## Bug report for Cloudinary Ruby SDK
The issue persists on https://rubygems.org/gems/cloudinary 2.4

## Describe the bug in a sentence or two.
Sometimes I get HTTP 404 when trying to fetch a .eml file (but the file exist in Cloudinary)

Initially reported in https://github.com/cloudinary/cloudinary_gem/issues/555

## Issue Type (Can be multiple)
- [ ] Build - Cannot install or import the SDK
- [ ] Performance - Performance issues
- [x] Behaviour - Functions are not working as expected (such as generate URL)
- [ ] Documentation - Inconsistency between the docs and behaviour
- [ ] Other (Specify)

## Steps to reproduce
- Start a new Rails project
- Set up [Action Mailbox](https://guides.rubyonrails.org/action_mailbox_basics.html) with Cloudinary as service
- Run the rails server, visit `/rails/conductor/action_mailbox/inbound_emails/` and create a few inbound emails
- You must see the error `Error performing ActionMailbox::RoutingJob` in the logs (it doesn't happen for all inbound emails, so be patient and keep adding them)

## Operating System
- [ ] Linux
- [ ] Windows
- [x] macOS
- [ ] All

## Environment and Libraries (fill in the version numbers)
- Cloudinary Ruby SDK version - 2.4
- Ruby Version - 3.1.7
- Rails Version - 7.1.5.2
- Other Libraries (ActiveStorage, etc) - activestorage = 7.1.5.2, actionmailbox = 7.1.5.2

## Repository

If possible, please provide a link to a reproducible repository that showcases the problem

/rails/conductor/action_mailbox/inbound_emails/ を通じて障害を再現することから始め、受信 .eml ファイルについて Error performing ActionMailbox::RoutingJob のパスを追跡します。Cloudinary Active Storage 統合を調査し、既存のすべての受信メールを HTTP 404 応答なしで取得できることを確認します。

索引モデルが issue の本文から書いたものです。