Prior to this change, the MFE would fail to render with any PUBLIC_PATH
set. Because that is now handled entirely by `frontend-platform`, we
can avoid referring to PUBLIC_PATH entirely, here.
* clean up and test segment integration
* add tests for action utils
* add tests for store aggregator and utils
* clean up un-used paths in thunkAction testUtils
* clean up filter reducer coverage
* add filter reducer tests for filterMenu actions
* clean up grades selectors coverage
* separate App and add unit tests
* ignore external files in coverage analysis
* remove old/unused code from StrictDict and clean up tests
* clean up FileUploadForm coverage
* more cleanup for StrictDict tests
* clean up GradesTab test coverage
* clean up GradesTab coverage
* ignore reducer-mapping for unit-test coverage
* clean up AssignmentFilter test coverage
* add index-level test coverage
* temp remove snapshots
* re-add App snapshot
* v1.4.41
