Bug: File upload broken on Rocket.Chat 8.x (uses removed rooms.upload endpoint)

[Aryan-Verma-999]

Description:

EmbeddedChat uses the rooms.upload/:rid endpoint for file uploads, which was deprecated in RC 6.10 and removed in RC 8.0. This means file uploads are completely broken for anyone running Rocket.Chat 8.x.

Steps to reproduce:

1. Connect EmbeddedChat to a Rocket.Chat 8.x server
2. Try to upload a file/image in chat
3. Upload fails silently or returns 404

Expected behavior:

File upload should work using the new rooms.media/:rid endpoint (two-step upload + confirm flow).

Reference:

RC Deprecated Endpoints