Drop TranscriptionType

• 1 MR on common to remove the enum
• 1 MR on the backend to remove Transcription.type and ElementType.allowed_transcription
• 1 MR on the frontend to remove transcription types (if present) and allowed_transcription
• 1 MR on tasks to remove transcription types and allowed_transcription
• 1 MR on base worker to deprecate transcription types
• 1 MR on the CLI's arkindex process report to handle transcription counts without types

Follow-ups

• Remove transcription types from every worker
• Remove transcription types from CaptchAN