tests: develop and write tests for steps/trace_segementation_clustering.py

[anujsinha3]

The Trace Segmentation Clustering code has been refactored from using CSV files to the pandas data frame.

The task is to develop and write tests for the code at: src/mawpy/steps/trace_segmentation_clustering.py

To write tests:

create a folder called 'steps' under the 'tests' folder
In the above folder, create a file called 'test_trace_segmentation_clustering.py'
define test functions corresponding to functions in src/mawpy/steps/trace_segementation_clustering.py

[anujsinha3]

@gracejia513 @Anurag19101996