Diagnoser WriteToCrd broken during recent refactor

[davidkydd]

Describe the bug
Diagnoser WriteToCrd broken in cce8000

How bug surfaces
When running periscope, diagnosers fail to update the CRD, logging shows:
2021/07/09 04:19:54 Diagnoser: networkoutbound, diagnose data failed: write data from NetworkOutbound Diagnoser to CRD: open [{"HostName":"aks-agentpool-14754340-vmss000000","Type":"AKS API Server","Start":"2021-07-09T04:17:24Z","End":"2021-07-09T04:17:24Z","Status":"Connected"},{"HostName":"aks-agentpool-14754340-vmss000000","Type":"AKS Tunnel","Start":"2021-07-09T04:17:24Z","End":"2021-07-09T04:17:24Z","Status":"Error: dial tcp 20.62.238.205:9000: connect: connection refused"},{"HostName":"aks-agentpool-14754340-vmss000000","Type":"Azure Container Registry","Start":"2021-07-09T04:17:24Z","End":"2021-07-09T04:17:24Z","Status":"Connected"},{"HostName":"aks-agentpool-14754340-vmss000000","Type":"Microsoft Container Registry","Start":"2021-07-09T04:17:24Z","End":"2021-07-09T04:17:24Z","Status":"Connected"},{"HostName":"aks-agentpool-14754340-vmss000000","Type":"Internet","Start":"2021-07-09T04:17:24Z","End":"2021-07-09T04:17:24Z","Status":"Connected"}]: file name too long
2021/07/09 04:19:54 Diagnoser: networkconfig, diagnose data failed: write data from NetworkConfig Diagnoser to CRD: open {"HostName":"aks-agentpool-14754340-vmss000000","NetworkPlugin":"","VirtualMachineDNS":null,"KubernetesDNS":["10.0.0.10\nsearch"],"MaxPodsPerNode":0}: no such file or directory

Additional context
Fix for Arc fork can be seen here: davidkydd@ba215e5