Enable instance annotations for null value nested resource or without value nested resource

[xuzhg]

Issues

This pull request fixes #3440: Missing annotations for null value nested resource or without value nested resource.

Description

When writing the nested resource, we can see the ODL retrieves the instance annotations from ODataNestedResourceInfo and write them as property annotation if the nested resource value is null.

So, this design makes sense but there's no way for developer to specify the instance annotations for ODataNestedResourceInfo since the 'SetInstanceAnnotation()is internal API. This also blocks to read the instance annotations fornull` value nested resource.

This PR is to expose the instance annotations on the ODataNestedResourceInfo. Then

in reading, upper layer can retrieve the instance annotations.

in writing, upper layer can set the instance annotations.

Briefly describe the changes of this pull request.

Checklist (Uncheck if it is not completed)

• Test cases added
• Build and test with one-click build and test script passed

Additional work necessary

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