feat(nbstore): remove async on connection api (#9187)

We should not use async on `connect` and `disconnect`, for `WebSocketConnection` will never connect when offline.

We should handle the connection status of each storage in sync, using the `connection.waitForConnect`

This PR also puts the connection reference count on the `connect` and disconnect`

packages/common/nbstore/src/impls/idb/doc.ts

@@ -1,4 +1,3 @@
-import { share } from '../../connection';
 import {
   type DocClock,
   type DocClocks,
@@ -17,7 +16,7 @@ interface ChannelMessage {
 }
 
 export class IndexedDBDocStorage extends DocStorage {
-  readonly connection = share(new IDBConnection(this.options));
+  readonly connection = new IDBConnection(this.options);
 
   get db() {
     return this.connection.inner.db;