Remove `#[test]` attributes from doc tests (#4214)

## Motivation and Context
This PR cleans up doc tests by removing `#[test]` attributes from code
snippets to prevent them from being executed. We've observed logs
indicating that some doc snippets have been running for over 60 seconds,
even though they are annotated with `no_run`.

In addition, this PR also removes duplicated example snippets that
previously took up a lot of space.

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Co-authored-by: Landon James <lnj@amazon.com>