NIFI-6468: TestListS3 assertion fix

[turcsanyip]

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Enables X functionality; fixes bug NIFI-YYYY.

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[pvillard31]

With the recent merge of the AWS Encryption service, we had the similar issue again on another test:

[ERROR] Failures: 
[ERROR]   TestFetchS3Object.testGetPropertyDescriptors:241 size should be eq expected:<18> but was:<19>

I manually fixed it before merging. +1 thanks @turcsanyip