utils package test coverage increase

[Tlacenka]

This issue is a part of the efforts in stabilising the tests #262 . Any checkbox may be converted into a standalone issue and completed.

• [ ] Missing coverage for formatReportScore.
• [x] Missing coverage for getRoundScoreMarker.
• [x] Missing coverage for getSquaredScoreMarker.
• [ ] Missing coverage for getSeverityIcon.
• [ ] Missing coverage for formatDuration (and unclear behaviour from my side - why fixed decimals?).
• [ ] Missing coverage for countCategoryAudits (and unclear behaviour from my side)
• [ ] Missing coverage for tableHtml.
• [ ] Increase coverage for countWeightedRefs (multiple weighed instances, weight 0.x).
• [ ] Add a JSON happy path test for loadReport.
• [ ] Add nested value examples for toArray, objectToKeys and objectToEntries.