Add matrix_rtc_session config options + bump js-sdk (#2756)

* Add matrix_rtc_session config options
* Bump js-sdk

https://github.com/matrix-org/matrix-js-sdk/compare/6971e7bebaad643c233e5057da7a0d42441c0789...fcb69b16ad8d170c67ea844f83543d467bbd7707

Also brings in:

- https://github.com/matrix-org/matrix-js-sdk/pull/4342
- https://github.com/matrix-org/matrix-js-sdk/pull/4494

src/config/ConfigOptions.ts

@@ -96,6 +96,30 @@ export interface ConfigOptions {
    * Note that this can additionally be disabled by the app's URL parameters.
    */
   app_prompt?: boolean;
+
+  /**
+   * These are low level options that are used to configure the MatrixRTC session.
+   * Take care when changing these options.
+   */
+  matrix_rtc_session?: {
+    /**
+     * How long (in milliseconds) to wait before rotating end-to-end media encryption keys
+     * when someone leaves a call.
+     */
+    key_rotation_on_leave_delay?: number;
+
+    /**
+     * How often (in milliseconds) keep-alive messages should be sent to the server for
+     * the MatrixRTC membership event.
+     */
+    membership_keep_alive_period?: number;
+
+    /**
+     * How long (in milliseconds) after the last keep-alive the server should expire the
+     * MatrixRTC membership event.
+     */
+    membership_server_side_expiry_timeout?: number;
+  };
 }
 
 // Overrides members from ConfigOptions that are always provided by the

src/rtcSessionHelpers.ts

@@ -98,8 +98,9 @@ export async function enterRTCSession(
 
   // right now we assume everything is a room-scoped call
   const livekitAlias = rtcSession.room.roomId;
+  const { features, matrix_rtc_session: matrixRtcSessionConfig } = Config.get();
   const useDeviceSessionMemberEvents =
-    Config.get().features?.feature_use_device_session_member_events;
+    features?.feature_use_device_session_member_events;
   rtcSession.joinRoomSession(
     await makePreferredLivekitFoci(rtcSession, livekitAlias),
     makeActiveFocus(),
@@ -108,6 +109,11 @@ export async function enterRTCSession(
       ...(useDeviceSessionMemberEvents !== undefined && {
         useLegacyMemberEvents: !useDeviceSessionMemberEvents,
       }),
+      membershipServerSideExpiryTimeout:
+        matrixRtcSessionConfig?.membership_server_side_expiry_timeout,
+      membershipKeepAlivePeriod:
+        matrixRtcSessionConfig?.membership_keep_alive_period,
+      makeKeyDelay: matrixRtcSessionConfig?.key_rotation_on_leave_delay,
     },
   );
 }