BaseNode sync - wait until stream is ready

[tomaszantas]

Related to the 2nd issue from #385

In onboarding, when user clicks Sync blockchain button, the app starts Tor + Base Node, and start listening to the Base Node stream. But Base Node needs a few seconds until it can open the stream.

The fe now waits 10 sec before it starts the listener. An ideal solution would be a periodic check done by fe. Backend prints this error already in console:

ERROR tari_launchpad::base_node_grpc] Failed reading progress from base node: status: Unknown, message: "transport error", details: [], metadata: MetadataMap { headers: {} }

... but it's not forwarded to the fronted. So the suggested fix is:

• backend returns the error to the frontend
• frontent tries to open the listener. If fails, wait a moment and repeat. (+ add limit on number of attempts)