fix: Remove reference to NETFramework.ReferenceAssemblies

[benjiro]

This PR

Since turning on CPM the code coverage build has broken, see here

Believe we don't need to reference this anymore as its being implicitly included

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (0a7e98d) 93.50% compared to head (57d60f6) 93.50%. Report is 4 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #219 +/- ## ======================================= Coverage 93.50% 93.50% ======================================= Files 23 23 Lines 954 954 Branches 105 105 ======================================= Hits 892 892 Misses 38 38 Partials 24 24 ```

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[austindrenski]

@benjiro I'm not sure why dotnet test is reporting an error when including the reference assemblies in that report workflow.

AFAIK those reference assemblies don't come for free with the .NET SDK on Linux, which is why we have to include them manually. I know that was at least true in the past, so I guess it might have changed, but idk...

Any chance it's something about codecover being included?

[austindrenski]

Wait scratch that, looks like this workflow might just have gotten messed up?

It looks like it's referencing a matrix variable without defining the strategy matrix:

[austindrenski]

Going to try addressing this as part of #196 which is already cleaning up some other matrices