Extensions.Hosting can add multiple TracerProvider without disposing old

[cijothomas]

A code like below will add 2 instances of TracerProvider and new ones replace the old one. Old ones are not disposed when being overwritten.

var builder = new HostBuilder().ConfigureServices(services =>
            {
                services.AddOpenTelemetryTracing((builder) => builder.SetResource(Resources.Resources.CreateServiceResource("mys1")));
                services.AddOpenTelemetryTracing((builder) => builder.SetResource(Resources.Resources.CreateServiceResource("mys2")));
            });

Opening an issue to track as this was reported offline.