Move TC_DA_1_7.py that was merged in wrong location (#21813)

- Due to switching between several environments, PR #21175
  had TC_DA_1_7.py in the root of the project rather than
  `src/python_testing` like other tests.

This PR moves the file to its correct location.

All prior testing was done with the root location (I checked
my command history), so it is the correct code/test, but
committed in the wrong place.