Pre-sets the screenshare id. Useful to automate or prepare stuff in advance.
If no value is passed, the system will automatically add the suffice of "_screenshare" to the existing stream ID that the user might be using.
When screen sharing as a guest in a group room, the screen share will now create a second stream for the screen share, keeping your webcam also.
This will preset the ID the screenshare will have, making things easier to predict and prep for.
Without this, the screen share ID is random, which is a decision made to increase security. This complication will be addressed in the future.