[V4] Update JSON error unmarshaller not to check for nested properties

[dscpinheiro]

Fixes #3764

Description

The SDK JSON (aws-restjson1 ) error unmarshaller checks for properties that end in certain values (the original spec is in the sdk-unmarshal-errors SEP). However, customers can request that DynamoDB return values whenever a PUT item fails due to a condition not being met.

If any properties in the customer model (which we don't control) also end with one of those suffixes, our unmarshaller fails. I updated it to only check for the values at the root level of the response.

This PR is for V4 as we have better coverage regarding protocol tests, but let me know if fixing it in V3 makes sense (from what I saw the logic has been in the SDK for quite some time and it's not a regression in V4).

Testing

• Dry-runs: DRY_RUN-77340fa6-b014-4138-9335-df03b1fad2c0 (.NET) and DRY_RUN-ef8c7677-19a9-4078-ae35-1027e13e061b (PowerShell)
• Ran the reproduction from the original issue and confirmed ConditionalCheckFailedException was thrown as expected

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the code style of this project
• I have added tests to cover my changes
• All new and existing tests passed

License

• I confirm that this pull request can be released under the Apache 2 license

[normj]

Given the users that reported the issue are still using v3.7 and looks to be a blocking issue for them we should back port the fix to V3.