Cleanup event E2E tests

[Nydauron]

Specifically:

• We should reduce the occurrences of magic numbers/magic strings
• Reference example events as variables (i.e. make events constant globals instead of duplicating the same event over multiple tests)
  • If an event needs to be modified, you can copy the struct locally and make any changes within the test (this would be the case for say the POST and PUT tests)