Add warning message to old unused package

[sima-zhu]

The original way of reading *.json under PackageInfo is not working at the case which artifact is under ci.yml but old mgmt which is not used anymore.
The PR is to skip the old unused package and throw warning message.

The test pipeline:
https://dev.azure.com/azure-sdk/internal/_build/results?buildId=1127833&view=results

[azure-sdk]

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[danieljurek]

We found this situation happening in other repos as well (.NET specifically but others could be impacted). After chatting with @weshaggard we should consider raising a warning when files are specified which do not have corresponding PackageInfo files.

This will prevent build errors and keep the processing logic identical.

We should also open up work items to enumerate all of the packages which don't produce PackageInfo so we can figure out if anything special needs to be done for those packages or their information in ci.yml

[azure-sdk]

The following pipelines have been queued for testing:
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java - template - tests
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python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
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[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
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net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[ghost]

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