Do Not Overwrite collectors

[naveensrinivasan]

Do not overwrite collectors

guac/pkg/handler/collector/collector.go

Lines 59 to 67 in 7176dec

	func RegisterDocumentCollector(c Collector, collectorType string) error {
	if _, ok := documentCollectors[collectorType]; ok {
	documentCollectors[collectorType] = c
	return fmt.Errorf("%w: %s", ErrCollectorOverwrite, collectorType)
	}
	documentCollectors[collectorType] = c
	return nil
	}

          re your [comment](https://github.com/guacsec/guac/pull/1500#issuecomment-1846097866) on this breaking things - is this behavior of overriding being used anywhere besides in tests? My initial thought is to add a comment for registration of collector to say that one should NOT override a registration (and should only be done for testing purposes). And then can you open an issue referencing this thread.

Originally posted by @lumjjb in #1500 (comment)

[arorasoham9]

Could I get some more information on what is required to be done here?