Codegen: Fix flipped conditional for the simple method warning log

Motivation and Context

Noticed during code generation there are warnings about not allowlisting certain operations as simple methods, but the warning doesn't actually apply because the methods do have required arguments.

Modifications

Fixed an improperly negated conditional -- implementation of the conditional didn't match the variable name stating what it should have been.

Testing

Unable to implement new testing due to the behavior being a logging-only behavior.
- The modified code does not affect anything at runtime

Screenshots (if appropriate)

Logged output

A potential simple method exists that isn't explicitly excluded or included: getThread

Applicable model snippet:

        "GetThreadInput": {
            "type": "structure",
            "required": [
                "threadId"
            ],

Types of changes

[x] Bug fix (non-breaking change which fixes an issue)
[ ] New feature (non-breaking change which adds functionality)

Checklist

[x] I have read the CONTRIBUTING document
[ ] Local run of mvn install succeeds
- Had environmental issues that prevented me from running successfully (running locally on a Mac laptop and running on a AL2 EC2 instance that has the IMDS port blocked in a weird way)
[x] My code follows the code style of this project
[ ] My change requires a change to the Javadoc documentation
[ ] I have updated the Javadoc documentation accordingly
[ ] I have added tests to cover my changes
[ ] All new and existing tests passed
[ ] I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
- I don't think this change necessitates a changelog entry
[ ] My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

[x] I confirm that this pull request can be released under the Apache 2 license

aws / aws-sdk-java-v2

Codegen: Fix flipped conditional for the simple method warning log #5558