Remove encryption_error

Author: Johennes

proposals/4196-matrixrtc-m-call.md

@@ -68,6 +68,8 @@ creator from sending state events. Including the slot event at room creation tim
 room members are able to have calls in the room without depending on a room administrator to send
 the slot event later.
 
+When using the `trusted_private_chat` preset in [`/createRoom`], 
+
 Including `m.rtc.slot` events in `initial_state` is not required when other `preset` values are
 used in [`/createRoom`]. With the `trusted_private_chat` preset, all room members get the same power
 level as the room creator. Thus, they can send the `m.rtc.slot` event themselves when needed. In
@@ -129,7 +131,6 @@ the following additional codes:
   (e.g. due to an ICE/DTLS setup failure).
 - `media_error`: The client failed to capture or transmit audio and/or video after joining.
 - `codec_mismatch`: The client could not decode/encode the call media.
-- `encryption_error`: The client failed to set up end-to-end encryption for the media channel.
 
 [below]: #faking-intent