Fix resource leaks when we stop using a connection

The execution of certain Observables related to a local or remote connection would continue even after we stopped caring about said connection because we were failing to give these state holders a proper ObservableScope of their own, separate from the CallViewModel's longer-lived scope. With this commit they now have scopes managed by generateKeyed$.

src/state/PublishConnection.ts

@@ -58,7 +58,7 @@ export class PublishConnection extends Connection {
     trackerProcessorState$: Behavior<ProcessorState>,
   ) {
     const { scope } = args;
-    logger.info("[LivekitRoom] Create LiveKit room");
+    logger.info("[PublishConnection] Create LiveKit room");
     const { controlledAudioDevices } = getUrlParams();
 
     const factory =