False-positive error page on frontend when node is restarted

[ozgunozerk]

After new error pages and node restart functionality, we have a new bug:

• When the node is restarted, the restart process is taking a bit of time.
• During this restart process, the frontend still tries to query the websocket via getSyncState()
• because the node is not available during that time, the query fails, and an error page is displayed with a restart option
• however, everything in the backend is working as expected
• if frontend can know about this, and waits for a few seconds, or waits for a signal from the backend, then frontend can stop querying the websocket.

Here is the further discussion about this: #305