[DRAFT] Unit Test Refactored Large Module and Clusterloader2Base classes

[nguyenluan3017]

Test Case	File Pattern	Component	Expected Result	Actual Result	Issue Description
1	GenericPrometheusQuery_testgroup_metricname_data.json	Measurement	metricname	'' (empty string)	The get_measurement method is not correctly extracting the metric name from GenericPrometheusQuery files. It should extract metricname from the filename pattern but returns empty string instead.
2	PodStartupLatency_PodStartupLatency_.json	Group Name	'' (empty string)	.json	The method is incorrectly parsing the group name when there's an empty group section (underscore followed by file extension). It should return empty string but returns .json instead.
3	APIResponsivenessPrometheus_.json	Group Name	'' (empty string)	.json	Similar to case 2, the method fails to handle empty group names correctly and returns the file extension instead of an empty string.

[sumanthreddy29]

@nguyenluan3017 , can you resolve merge conflicts? Pull latest changes and fix CI checks

[nguyenluan3017]

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