Refactor updateStopRules and add tests

[forsaken628]

What this PR does / why we need it:

Reorganize the scattered status. Add tests.
There should be a bug here. Step will be less than zero.

katib/cmd/metricscollector/v1beta1/file-metricscollector/main.go

Lines 360 to 365 in f8b8d8d

	if _, ok := metricStartStep[rule.Name]; ok {
	metricStartStep[rule.Name]--
	if metricStartStep[rule.Name] != 0 {
	return stopRules, optimalObjValue
	}
	}

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Checklist:

• Docs included if any changes are user facing

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[andreyvelich]

There should be a bug here. Step will be less than zero.

Thank you for refactoring these functions and add tests @forsaken628!
Please can you explain the use-case when step will be less than zero and why we don't catch this bug in our E2Es ?