No instances handling in Rest collector

[rahulguptajss]

When there are no instances in the REST collector, the collector no longer goes into standby mode. This behavior change was introduced in #3305. There is no functional impact due to this change. It affects the retry logic, determining when to attempt the poll next, which should be every 5 minutes. Currently, it follows the REST collector's schedule cycle for the next run.

time=2024-12-05T15:14:07.205+05:30 level=INFO source=collector.go:601 msg=Collected Poller=dc-1 collector=Rest:Volume apiMs=3750 bytesRx=162845 calcMs=0 exportMs=0 instances=0 instancesExported=1 metrics=0 metricsExported=1 numCalls=5 parseMs=0 pluginInstances=0 pluginMs=1681 pollMs=5433 renderedBytes=92 zBegin=1733391841772