Issue #, if available: N/A

Description of changes:

This improves the validation we do in the existing tests/functional/docs/test_examples.py. Previously we were only testing the service and operation name.

Now, it runs the example commands through the appropriate parser for each. This will catch more issues: invalid syntax, invalid argument names, missing required parameters.

This also fixes the examples that fail for the updated test.

Note: I did not address examples that specify --cli-input-json/etc., it'll require more work to parse and validate those.

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