Don't mark management disconnected on transient job stream errors (#6005)

The JOB stream is a separate channel from the SYNC stream. Server-side
EOF or other transient errors on the JOB stream do not indicate that
the management connection is unhealthy — the SYNC stream remains the
authoritative state signal.

Previously, a JOB stream EOF would call notifyDisconnected and the
client would emit OnConnecting to the UI. The backoff retry would
reconnect the JOB stream, but handleJobStream never calls notifyConnected
on success, so the UI was stuck on "Connecting" until the next SYNC
event or health check.

Keep notifyDisconnected for codes.PermissionDenied since IsLoginRequired
relies on managementError to detect expired auth.

shared/management/client/grpc.go

@@ -252,21 +252,19 @@ func (c *GrpcClient) handleJobStream(
 					c.notifyDisconnected(err)
 					return backoff.Permanent(err) // unrecoverable error, propagate to the upper layer
 				case codes.Canceled:
-					log.Debugf("management connection context has been canceled, this usually indicates shutdown")
+					log.Debugf("job stream context has been canceled, this usually indicates shutdown")
 					return err
 				case codes.Unimplemented:
 					log.Warn("Job feature is not supported by the current management server version. " +
 						"Please update the management service to use this feature.")
 					return nil
 				default:
-					c.notifyDisconnected(err)
-					log.Warnf("disconnected from the Management service but will retry silently. Reason: %v", err)
+					log.Warnf("job stream disconnected, will retry silently. Reason: %v", err)
 					return err
 				}
 			} else {
 				// non-gRPC error
-				c.notifyDisconnected(err)
-				log.Warnf("disconnected from the Management service but will retry silently. Reason: %v", err)
+				log.Warnf("job stream disconnected, will retry silently. Reason: %v", err)
 				return err
 			}
 		}