refactor(chat): Upload voice messages and contacts with a single implementation

[Ivansss]

Third step towards a single file upload implementation, on top of #2640.

Uploading a file into a conversation is the same three steps everywhere: resolve a destination, upload
it, announce it in the conversation. This adds one implementation of that and moves the voice message,
contact and resend paths onto it. The ShareConfirmationViewController changes will be done in a follow-up PR.

Behaviour changes:

• A 404 or 409 no longer retries into the attachment folder when the upload started in the draft
  folder, which silently turned a subfolder upload into a read only share in the Talk folder
• Shared contacts are posted with the contact name instead of a random UUID
• Resending a private reply voice message now sends replyToToken

Needs manual testing with conversation_subfolders enabled and disabled: voice message, shared
contact, and a failing upload.

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI