Unblock package upgrades after deprecating tests for .NET 4.6.2

[ForNeVeR]

An update to the following packages is currently blocked, because they don't support net462, and we still want to support that framework:

• xunit.runner.visualstudio v3
• ApprovalTests v7

We will likely support if until 2027-01-12, because it is supported by Microsoft until that date (see the lifecycle policy).

So, we cannot update until we run tests for .NET 4.6.2.

See TODO[#517] in the code for the exact place where the update is blocked.