Update M.E.AI* to depend on net10.0 nuget packages

[stephentoub]

[stephentoub]

cc: @eiriktsarpalis, @jeffhandley

[eiriktsarpalis]

Making System.Text.Json v10 the minimum version would also let us remove the JsonSchemaExporter polyfill, which is its own separate implementation and has known issues related to trimming.