/addwidget <Jitsi URL> prepends slash to Jitsi conference ID

[AndrewFerr]

Steps to reproduce

1. Use the Jitsi web client for the Jitsi domain an Element/Synapse is configured to use, and create & join a new conference with an ID of your choice
2. In Element Web, issue the /addwidget command to create a conference call widget for that conference ID
3. Join the conference call widget

Outcome

What did you expect?

The conference shown in the Element widget should be the same as the one created in the external Jitsi client, and members who join from either the Element widget or the Jitsi client should join the same conference.

What happened instead?

Joining from the Element widget will join a different conference than the one created from the external Jitsi client.

The Element widget's conference ID differs by always containing a leading slash.

For example, /addwidget https://your.jitsi.domain/customConfID will set data.conferenceID: "/customConfID" in the widget event's content.

Operating system

No response

Browser information

No response

URL for webapp

Self-hosted Element v1.9.4

Application version

No response

Homeserver

No response

Will you send logs?

No