send hangup when leaving the call

but not when somebody else leaves the call through a member event

src/matrix/calls/group/GroupCall.ts

@@ -269,7 +269,7 @@ export class GroupCall extends EventEmitter<{change: never}> {
         if (this._state === GroupCallState.Joined) {
             log.set("leave_own", true);
             for (const [,member] of this._members) {
-                member.disconnect();
+                member.disconnect(true);
             }
             this._localMedia?.dispose();
             this._localMedia = undefined;
@@ -286,7 +286,7 @@ export class GroupCall extends EventEmitter<{change: never}> {
             if (member) {
                 log.set("leave", true);
                 this._members.remove(memberKey);
-                member.disconnect();
+                member.disconnect(false);
             }
             this.emitChange();
         });

src/matrix/calls/group/Member.ts

@@ -99,9 +99,13 @@ export class Member {
     }
 
     /** @internal */
-    disconnect() {
+    disconnect(hangup: boolean) {
         this.logItem.wrap("disconnect", log => {
+            if (hangup) {
+                this.peerCall?.hangup(CallErrorCode.UserHangup);
+            } else {
                 this.peerCall?.close(undefined, log);
+            }
             this.peerCall?.dispose();
             this.peerCall = undefined;
             this.localMedia?.dispose();