fix: handle custom file of status_7mode object

[Hardikl]

Tested locally with custom.yaml file with this content

objects:
  Status_7mode:    status_7_custom.yaml

./bin/poller -p sarzapi --promPort 13006 -o Status_7mode -c Zapi --config harvestopenlab.yml
2023-04-12T14:12:32+05:30 INF ./poller.go:205 > Init Poller=sarzapi configPath=harvestopenlab.yml logLevel=info version="harvest version 23.04.1214-v23.02.0 (commit d830c6c7) (build date 2023-04-12T14:12:12+0530) darwin/amd64\n"
2023-04-12T14:12:32+05:30 INF ./poller.go:242 > started in foreground Poller=sarzapi pid=88976
2023-04-12T14:12:33+05:30 INF ./poller.go:1215 > Use ZAPIs HARVEST_NO_COLLECTOR_UPGRADE= Poller=sarzapi collector=Zapi preferZAPI=true v=9.12.1
2023-04-12T14:12:34+05:30 WRN ./poller.go:331 > no collectors initialized, stopping Poller=sarzapi
2023-04-12T14:12:34+05:30 INF ./poller.go:556 > cleaning up and stopping [pid=88976] Poller=sarzapi