Keep screenshares when switching focus

This also removes the use of the useLivekitRoom hook: we had reached
the point where the only thing it was actually doing was disconnecting,
so we now do that in the onClick handler for the leave button (I don't
think we need to disconnect on unmount?). It was otherwise just getting in
the way and causing tracks to be enabled/disabled when we didn't want them
to be. This also removes the need for the blockAudio code.

Fixes https://github.com/vector-im/element-call/issues/1413

src/livekit/useLiveKit.ts

@@ -22,8 +22,7 @@ import {
   RoomOptions,
   Track,
 } from "livekit-client";
-import { useLiveKitRoom } from "@livekit/components-react";
-import { useEffect, useMemo, useRef, useState } from "react";
+import { useEffect, useMemo, useRef } from "react";
 import E2EEWorker from "livekit-client/e2ee-worker?worker";
 import { logger } from "matrix-js-sdk/src/logger";
 import { MatrixRTCSession } from "matrix-js-sdk/src/matrixrtc/MatrixRTCSession";
@@ -118,11 +117,6 @@ export function useLiveKit(
     [e2eeOptions],
   );
 
-  // useECConnectionState creates and publishes an audio track by hand. To keep
-  // this from racing with LiveKit's automatic creation of the audio track, we
-  // block audio from being enabled until the connection is finished.
-  const [blockAudio, setBlockAudio] = useState(true);
-
   // Store if audio/video are currently updating. If to prohibit unnecessary calls
   // to setMicrophoneEnabled/setCameraEnabled
   const audioMuteUpdating = useRef(false);
@@ -137,19 +131,11 @@ export function useLiveKit(
   // We have to create the room manually here due to a bug inside
   // @livekit/components-react. JSON.stringify() is used in deps of a
   // useEffect() with an argument that references itself, if E2EE is enabled
-  const roomWithoutProps = useMemo(() => {
+  const room = useMemo(() => {
     const r = new Room(roomOptions);
     r.setE2EEEnabled(e2eeConfig.mode !== E2eeType.NONE);
     return r;
   }, [roomOptions, e2eeConfig]);
-  const { room } = useLiveKitRoom({
-    token: sfuConfig?.jwt,
-    serverUrl: sfuConfig?.url,
-    audio: initialMuteStates.current.audio.enabled && !blockAudio,
-    video: initialMuteStates.current.video.enabled,
-    room: roomWithoutProps,
-    connect: false,
-  });
 
   const connectionState = useECConnectionState(
     {
@@ -160,11 +146,6 @@ export function useLiveKit(
     sfuConfig,
   );
 
-  // Unblock audio once the connection is finished
-  useEffect(() => {
-    if (connectionState === ConnectionState.Connected) setBlockAudio(false);
-  }, [connectionState, setBlockAudio]);
-
   useEffect(() => {
     // Sync the requested mute states with LiveKit's mute states. We do it this
     // way around rather than using LiveKit as the source of truth, so that the