Make HTML test result files more readable

[rfrenchseti]

• Fixes #1280
• Were any Django, import pipeline, or table_schema files modified? Y
  • If YES:
  • Database used (or new import): opus3_test_231128
  • FLAKE8 run on modified code: Y
  • All Django tests pass: Y
  • Code coverage run and still at 100%: Y
• Were any JavaScript or CSS files modified? N
  • If YES:
  • JSHINT run on all affected files: Y/NA
  • Tested on Chrome, Firefox, Safari, Edge, and iOS: Y/NA (Remember to test all browser sizes)
  • Tested for race conditions (with delayed API calls if applicable): Y/NA
• Was the documentation reviewed for necessary changes or additions? NA
  • About
  • Getting Started
  • FAQ
  • API Guide
  • Tooltips
  • Import/database schema

Description of changes:

When HTML responses are saved to a file, they used to include the string \n instead of an actual newline. This meant that the entire response was returned on a single line, making it impossible to use "diff" to figure out what changed. This pull changes that and now stores the files with actual newlines in them instead making diffs much more useful.

Known problems:

None.

[codecov[bot]]

Welcome to Codecov :tada:

Once merged to your default branch, Codecov will compare your coverage reports and display the results in this comment.

Thanks for integrating Codecov - We've got you covered :open_umbrella: