[2.4.0] Checkmk Werk 16606 created: agent_netapp_ontap: handle shelves without elements

[//]: # (werk v2) # agent_netapp_ontap: handle shelves without elements key | value ---------- | --- date | 2024-04-10T12:26:35+00:00 version | 2.4.0b1 class | fix edition | cre component | checks level | 1 compatible | yes The agent did not handle the cases where shelves had no fans, temperature sensors or PSUs. This led to crashes during the agent execution. With this werk we know correctly handle these scenarios and the corresponding services are not discovered if no items are found.