ENT-1588: Logic to determine value of `has_passed` column changed

[ziafazal]

Logic to determine value of has_passed column should take into consideration value of letter_grade. There are some case when we have value in passed_timestamp but value in letter_grade is empty these cases should have a False value in has_passed column. ENT-1588

Make sure that the following steps are done before merging:

• [ ] If you have a migration please contact data engineering team before merging.
• [ ] Before merging run full acceptance tests suite and provide URL for the acceptance tests run.
• [x] A member of data engineering team has approved the pull request.

[codecov[bot]]

Codecov Report

Merging #760 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #760   +/-   ##
=======================================
  Coverage   74.55%   74.55%           
=======================================
  Files         207      207           
  Lines       23420    23420           
=======================================
  Hits        17461    17461           
  Misses       5959     5959

Impacted Files	Coverage Δ
...alytics/tasks/enterprise/enterprise_enrollments.py	83.87% <ø> (ø)	:arrow_up:
...ks/tests/acceptance/test_enterprise_enrollments.py	40% <ø> (ø)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 10b5a83...e4556b2. Read the comment docs.