Dropped .Net Standard 2.0 in 3.0.0 causes dependent package complications

[johnthcall]

A large number of packages which depend on Microsoft.ApplicationInsights publish with .Net Standard 2.0. For example MsTest via Microsoft.Testing.Extensions.Telemetry. By dropping support in #3091 these packages either need to stay on 2.23.0 forever or drop .net standard 2.0 and force a similar decision on all their consumers. Raised the following issue to make MsTest aware of this issue: microsoft/testfx#7465