MatrixRTCSessionManager is tracking encryption keys even when not needed #2566
Description
Currently the js-sdk always tracks the encryption keys even if the client never does anything with media.
The impact at the moment is two fold:
- Element Web is doing unnecessary duplicate tracking of encryption keys
- It makes for confusing log lines like in Per participant key lost between js-sdk and EC in embedded mode #2561
Proposal: we make it so that MatrixRTCSessionManager doesn't track encryption keys by default, but instead the client has to call something like MatrixRTCSessionManager.startTrackingEncryptionKeys() which EC would use.