privval: retry GetPubKey/SignVote/SignProposal N times before

returning an error

Closes #4707

node/node.go

@@ -1310,15 +1310,27 @@ func createAndStartPrivValidatorSocketClient(
 ) (types.PrivValidator, error) {
 	pve, err := privval.NewSignerListener(listenAddr, logger)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to start private validator")
+		return nil, fmt.Errorf("failed to start private validator: %w", err)
 	}
 
 	pvsc, err := privval.NewSignerClient(pve)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to start private validator")
+		return nil, fmt.Errorf("failed to start private validator: %w", err)
 	}
 
-	return pvsc, nil
+	// try to get a pubkey from private validate first time
+	_, err = pvsc.GetPubKey()
+	if err != nil {
+		return nil, fmt.Errorf("can't get pubkey: %w", err)
+	}
+
+	const (
+		retries = 50 // 50 * 100ms = 5s total
+		timeout = 100 * time.Millisecond
+	)
+	pvscWithRetries := privval.NewRetrySignerClient(pvsc, retries, timeout)
+
+	return pvscWithRetries, nil
 }
 
 // splitAndTrimEmpty slices s into all subslices separated by sep and returns a