Refactor tests for survey response import

[kael89]

[No issue]

Not strictly required but in preparation for PHX-152, I felt that it would be worth refactoring the survey response import tests. Reasons:

• I found it a bit hard to get an overview of the existing test cases
• These tests use some older patterns. Refactoring to use newer setup and test data patterns should make them more maintainable

Changes overview

1. Used semantic test ids (eg duplicate_quest_id1_test) instead of the existing, more realistic ids (eg fdfcc42a44705c032a8_test)
2. Removed redundant test data (multiple responses testing the same logic, unnecessary models eg assign a Public permission group to a survey when permissions are not tested, etc)
3. Extracted validation tests in their own file and parameterised them
4. Updated the import spreadsheets according to the new changes + restructured them a bit

[IgorNadj]

Thanks for cleaning that up!