feat: Add Amazon SES inbound email support (#12893)

## Summary
- add AWS ActionMailbox SES gems
- document SES as incoming email provider
- note SES option in configuration

## Testing
- `bundle exec rubocop config/initializers/mailer.rb
config/environments/production.rb Gemfile`


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[Codex
Task](https://chatgpt.com/codex/tasks/task_e_68bbb7d482288326b8f04bb795af0322)

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Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: Vinay Keerthi <11478411+stonecharioteer@users.noreply.github.com>

config/initializers/mailer.rb

@@ -46,5 +46,9 @@ Rails.application.configure do
   # :mandrill for Mandrill
   # :postmark for Postmark
   # :sendgrid for Sendgrid
+  # :ses for Amazon SES
   config.action_mailbox.ingress = ENV.fetch('RAILS_INBOUND_EMAIL_SERVICE', 'relay').to_sym
+
+  # Amazon SES ActionMailbox configuration
+  config.action_mailbox.ses.subscribed_topic = ENV['ACTION_MAILBOX_SES_SNS_TOPIC'] if ENV['ACTION_MAILBOX_SES_SNS_TOPIC'].present?
 end