refactor: changed create_user with UserFactory to avoid errors

[mariajgrimaldi]

Description

This PR replaces User.objects.create_user references with UserProfile.create, to automatically create the user's profile avoiding tests errors.

Supporting information

This was discussed -here- after we encountered some errors while using the user's profile in some tests. For example here:
https://build.testeng.edx.org/job/edx-platform-python-pipeline-pr/33620/#showFailuresLink
More in detail:
https://build.testeng.edx.org/job/edx-platform-python-pipeline-pr/33620/testReport/junit/lms.djangoapps.course_goals.tests.test_goals/TestCourseGoalsAPI/Run_Tests___lms_unit___test_add_goal/

Testing instructions

Run edxapp tests:

1. Run specific tests:
   pytest lms/djangoapps/course_goals/tests/test_goals.py::TestCourseGoalsAPI::test_add_goal
2. Run specific test suit: paver test_js_run -s <lms|cms>

Deadline

"None"

Other information

This PR just improves tests by adding missing data.

[openedx-webhooks]

Thanks for the pull request, @mariajgrimaldi! I've created OSPR-5984 to keep track of it in JIRA, where we prioritize reviews. Please note that it may take us up to several weeks or months to complete a review and merge your PR.

Feel free to add as much of the following information to the ticket as you can:

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Please let us know once your PR is ready for our review and all tests are green.

[edx-status-bot]

Your PR has finished running tests. There were no failures.

[mariajgrimaldi]

Hey @felipemontoya, I hope you're doing great!

As a core committer, what do you think about these improvements? Any feedback is welcome.

[felipemontoya]

This looks great. Overall it improves the test quality, removes some warnings left from the lint amnesty and it will fix the errors we have on the events PR.

[felipemontoya]

Since this PR is maintenance only, I believe it is ok to merge it with only one CC approval.

[edx-pipeline-bot]

EdX Release Notice: This PR has been deployed to the staging environment in preparation for a release to production.

[edx-pipeline-bot]

EdX Release Notice: This PR has been deployed to the production environment.

[natabene]

@mariajgrimaldi @felipemontoya Thank you both!

[openedx-webhooks]

@mariajgrimaldi 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.