Bug with RdRichValueWebImagePart of Open XML SDK

[seanblac8]

Describe the bug
If I use Open XML SDK 3.02 to read a xlsx file, /xl/richData/rdRichValueWebImage.xml of xlsx file is a DocumentFormat.OpenXml.Packaging.ExtendedPart instead of RdRichValueWebImagePart.

The workbook has _webimages, but the workbookPart.RdRichValueWebImagePart is null.

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To Reproduce
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Steps to reproduce the behavior:

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2. Click on '....'
3. Scroll down to '....'
4. See error

Observed behavior
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Expected behavior
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Desktop (please complete the following information):

• OS: [e.g. Windows]
• Office version [e.g. 16.0.15427.20178]
• .NET Target: (e.g. .NET Framework, .NET Core, UWP, Xamarin...)
• DocumentFormat.OpenXml Version: (e.g. 2.11.0)

Additional context
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