Update RegistryTests to support netstandard2.1 packages

[laicasaane]

Fix #705

Test with a streamlined registry.json:

• Pass all test cases
• Include DryDB
• Include MemoryPack

[laicasaane]

Since this PR #702 failed by the test Ensure_Min_Version_Is_Correct_Ignoring_Analyzers_And_Native_Libs, I figured we need to update the tests to account for netstandard2.1.

Disclaimer: I still don't understand the whole source code, so I don't know if we need to do anything to the server code beyond fixing this test.

[laicasaane]

The previous build failed because some packages support netstandard2.1 in an older version compared to the version which supports netstandard2.0.

[github-actions]

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