Tests not being run

[roussel-ryan]

Describe the bug
Unit tests for the emittance measurement class (tests/unit_tests/lcls_tools/common/measurements/test_emittance_measurement.py) are not being run, they should fail in the current state of the code.

To Reproduce
Reproduced every time "Python application" github action is run.

Expected behavior
Github action "Python application" should fail.

Additional context
The directory tests/unit_tests/lcls_tools/common/measurements/ is missing an init.py file. This is addressed in #218

[roussel-ryan]

I was able to fix the test not running and will address the error in the emittance measurement class. Track developments in #218