Span limits have wrong defaults

[Kielek]

Bug Report

List of all OpenTelemetry NuGet
packages and version that you are
using (e.g. OpenTelemetry 1.0.2):

Current main - post 1.4.0-beta.3.

Symptom

What is the expected behavior?

What did you expect to see?

Defaults are same as in https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md#span-limits

What is the actual behavior?

All of the limits are set to int.MaxValue when SdkLimitOptions return nulls..

Reproduce

Debug OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests.OtlpHttpTraceExportClientTests.NewOtlpHttpTraceExportClient_OtlpExporterOptions_ExporterHasCorrectProperties