Poor data cleanup after the SQL E2E tests leads to unexpected errors when running E2E tests

[mingyang143]

Steps to reproduce

1. In an E2E test, call feedbackEditPage.deleteSession().
2. Run the E2E test suite once.
3. Run the same E2E test suite again using the same json file for the E2E test,

Expected behaviour

• All entities created during the test should be deleted.
• Each E2E test run should start with a fresh database state, without any persisted values from previous runs.

Actual behaviour

• The second test run fails with: teammates.common.exception.HttpRequestFailedException: Request failed: [409] {"message":"Some entities in the databundle already exist","requestId":"586c09236d8bd7333f5f37de7b98217c"}.

Additional info

• The bug is further discussed in this PR: [#12048] Migrate InstructorFeedbackEditPageE2ETest #13314.
• However, it is unfixed at the moment.

• The only way to fix this issue is to change the JSON entity names.