fix: Prevent AudioTranscriptionJob from crashing on OpenAI 401 error (#13653)

Describe the bug
In v4.8.0, when an audio message is received, the system enqueues
Messages::AudioTranscriptionJob even if OpenAI and Captain are disabled.
This causes a Faraday::UnauthorizedError (401) which crashes the Sidekiq
job and breaks the pipeline for that message.

To Reproduce
Disable OpenAI/Captain integrations.

Send an audio message to an inbox.

Check Sidekiq logs and observe the 401 crash in
AudioTranscriptionService.

What this PR does
Adds a rescue Faraday::UnauthorizedError block inside
AudioTranscriptionService#perform. Instead of crashing the worker, it
logs a warning and gracefully exits, allowing the job to complete
successfully.

Note: This fixes the backend crash. However, there is still a frontend
reactivity issue where the audio player UI requires an F5 to load the
media, which has been reported in Issue #11013.

---------

Co-authored-by: Eloi Junior Seganfredo <eloi@seganfredo.local>
Co-authored-by: Aakash Bakhle <48802744+aakashb95@users.noreply.github.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

enterprise/app/services/messages/audio_transcription_service.rb

@@ -19,6 +19,9 @@ class Messages::AudioTranscriptionService< Llm::LegacyBaseOpenAiService
     transcriptions = transcribe_audio
     Rails.logger.info "Audio transcription successful: #{transcriptions}"
     { success: true, transcriptions: transcriptions }
+  rescue Faraday::UnauthorizedError
+    Rails.logger.warn('Skipping audio transcription: OpenAI configuration is invalid or disabled (401 Unauthorized).')
+    { error: 'OpenAI configuration is invalid or disabled (401)' }
   end
 
   private