Add JSON Serialization Support for OLE

[lonitra]

Related: #11368

This is a start to support JSON serialization in OLE scenarios.
JsonData<T>: This is our wrapper class that holds the JSON serialized data along with the original type information. Note that the data that is being JSON serialized uses default JsonSerializer behavior. Users can follow the remarks of the public APIs if custom JSON serialization behavior is needed.

Public APIs:

• DataObject.SetDataAsJson() - Allows users to add data to DataObject that will be JSON serialized. This is how we support JSON serialization for drag/drop scenario.
• Clipboard.SetDataAsJson() - Allows users to conveniently JSON serialize a type onto the clipboard, but note that this does not accept DataObject being passed in. If users want to place a DataObject on the clipboard, users should ensure data they want to be JSON serialized is already in the DataObject by utilizing DataObject.SetDataAsJson and then use Clipboard.SetDataObject().

Tests:

• Unit tests added for new APIs, some of the same tests also added in ComDisabledTests to ensure same behavior if built in com support is turned off.
• Manually tested cross process scenario -- drag/drop and copy/paste from 2 WinForms apps and confirmed able to retrieve the original data without exposing JsonData<T>
• Manually tested copying data onto clipboard from app running on main branch and pasting into .NET 8 app for informational purposes. This scenario currently does not work as one may expect likely due to JsonData<T> not existing in .NET 8. More investigation needs to be done here.
• Test behavior in trimmed app: JsonSerializer uses reflection to serialize by default, which will not be available when trimming is turned on. We will need to either use source generator APIs to support trimming or configure JsonSerializerOptions.TypeInfoResolver
  

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

Attention: Patch coverage is 97.30640% with 8 lines in your changes missing coverage. Please review.

Project coverage is 74.78245%. Comparing base (f024a86) to head (eba27ab).
Report is 1 commits behind head on feature/clipboard.

Additional details and impacted files

@@                     Coverage Diff                     @@
##           feature/clipboard      #11527         +/-   ##
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+ Coverage           74.74065%   74.78245%   +0.04179%     
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  Files                   3045        3045                 
  Lines                 630626      630886        +260     
  Branches               46860       46874         +14     
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+ Hits                  471334      471792        +458     
+ Misses                155932      155724        -208     
- Partials                3360        3370         +10     

Flag	Coverage Δ
Debug	74.78245% <97.30640%> (+0.04179%)	⬆️
integration	17.95274% <6.55738%> (-0.00847%)	⬇️
production	47.84703% <90.16393%> (+0.08041%)	⬆️
test	96.98654% <99.15254%> (+0.00120%)	⬆️
unit	44.89268% <90.16393%> (+0.08380%)	⬆️

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[JeremyKuhne]

Generally looks good, some minor comments.

[JeremyKuhne]

I'd put this string in the JsonData type as a constant with a comment.

[JeremyKuhne]

While you don't technically need IObjectReference for our usages, the workaround for Clipboard versions that don't know of this type would be to copy this with IObjectReference. You can comment to that effect. Writing a test to capture this behavior would be good too.

The test should use the writer code to manually write a JsonData object to a stream, then you can read it with the deserializer and a binder that redirects to this actual type.

[elachlan]

@willibrandon you might be interested in the clipboard work here.