Implement new MIBs using telemetry-based model

Junos OS supports, new MIBs mplsMldpInterfaceStatsEntry and mplsMldpFecUpstreamSessTable are introduced. The Routing Engine uses a telemetry-based approach to collect statistics to provide MIB data for these MIBs. A new statement, sensor-based-stats at the [edit protocols ldp traffic-statistics] hierarchy level, enables telemetry-based collection. You must configure this statement to enable MIB data collection for mplsMldpInterfaceStatsEntry and mplsMldpFecUpstreamSessTable.