Cannot filter livechat history messages with "ts" queryparameter

Description:

Not possible to use "ts" query parameter to filter livechat history messages. Parameter is ignored.

Steps to reproduce:

1. As a guest, open a new live chat.
2. Send a couple of messages
3. Using the REST API to load the Livechat history and specify the "ts"parameter to only retrieve the latest message

Example:
https://myserver.rocket.chat/api/v1/livechat/messages.history/myroomid?token=guestToken&ls=2021-02-19T12:39:53.746Z

Expected behavior:

The history should only return messages AFTER the given timestamp.

Actual behavior:

All messages are returned.

Server Setup Information:

• Version of Rocket.Chat Server: 3.10.5
• Commit: 1e36f4183852248cece3b1ad092bc566a8cfbd52
• Operating System: Linux
• Deployment Method: Cloud
• Number of Running Instances: 1
• DB Replicaset Oplog: wiredTiger
• NodeJS Version: v12.18.4
• MongoDB Version: 4.2.8
• Deployment ID: uMe4Y5PA8XksWcbRr

Client Setup Information

• Desktop App or Browser Version: Chrome
• Operating System: Windows 10 1803

Additional context

If there is no magic that I don't see the parameter is actually called ls (found here but called ts in the documentation.

Either way, neither of the parameters does anything.

Not sure if the documentation is missing something or if I'm doing something wroing.

Start with app/livechat/server/api/v1/message.js at the referenced history endpoint, then compare its query parameter name and behavior with the linked REST API documentation. Reproduce the request using the provided guest-chat steps and timestamp. Done means the documented parameter and endpoint behavior agree and history results are filtered after the supplied timestamp.