BLE Mesh After restart, no heartbeat packets

[goodwell]

MCU:nRF52832

SDK:nRF5_SDK_15.2.0_9412b96

MESH SDK:nrf5SDKforMeshv310src

The First Join Mesh Network，Client can normally enter health_publish_timeout_handler function. After restart, no heartbeat packet can enter health_publish_timeout_handler function. Provisioner has been kept on normal online.

[Hung Bui]

Hi Goodwell, 

Similar to health publication, heartbeat publication is not restored automatically after a reset. This is according to spec. There is a discussion about that and a workaround here: https://devzone.nordicsemi.com/f/nordic-q-a/29611/mesh-health-model#post-id-189330.