Set ProducesDotNetReleaseShippingAssets property in Publishing.props

[MilenaHristova]

Add a boolean property named ProducesDotNetReleaseShippingAssets in Publishing.props for repos that produce .NET shipping packages (packages that we ship with the release infra)
Based on this property we will select which packages to ship as part of .NET on release day.

This is a infrastructure only change. It will add extra metadata to the MergedManifest.xml produced during CI build.

Issue: https://github.com/dotnet/release/issues/822

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ab13ac7) 96.45% compared to head (34df03e) 96.45%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7206   +/-   ##
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  Coverage   96.45%   96.45%           
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  Files        1422     1422           
  Lines      340585   340585           
  Branches    11230    11230           
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+ Hits       328511   328520    +9     
+ Misses       9236     9227    -9     
  Partials     2838     2838           

[buyaa-n]

IDK what it does, but approving and merging as @ericstj approved.

[ericstj]

Per the linked issue above - it's a property being set in all shipping repos.