Refactor event reporting usage to remove redundant code

[hensmi-amazon]

Issue #: None. I was going to extend some of these events and figured i could clean up the existing usage first.

Description of changes: Purely cosmetic. Change to using helper function for consistency.

Testing: I (+ gen AI) compared all events before and after change to confirm they had the same values.

Can these tested using a demo application? Please provide reproducible step-by-step instructions.

Yes, but it takes a lot of log comparison so I won't recommend it here.

1. Have you successfully run npm run build:release locally?

y

2. Do you add, modify, or delete public API definitions? If yes, has that been reviewed and approved?

n

3. Do you change the wire protocol, e.g. the request method? If yes, has that been reviewed and approved?

n

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.