Setting OTEL_TRACES_SAMPLER_ARG=always_off results in no spans being exported

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According to https://opentelemetry-python.readthedocs.io/en/latest/sdk/trace.sampling.html setting OTEL_TRACES_SAMPLER_ARG=always_off should turn off sampling allowing all the spans to go through to the collector. However what actually ends up happening is that no spans are sent. This needs a clarification in the docs or some update in the behavior of that setting. Per https://github.com/open-telemetry/opentelemetry-python/issues/3474#issuecomment-1771355829, it seems like the expected behavior this effectively stops spans from being exported.

Steps to reproduce
Set OTEL_TRACES_SAMPLER_ARG=always_off

What is the expected behavior?
What did you expect to see?
Expect all samples to be sent to collector

What is the actual behavior?
What did you see instead?
No spans are sent to the collector

Additional context
Version: 0.44b0

Start with the trace sampling documentation linked in the issue and review the behavior described in issue #3474's linked comment. Reproduce with OTEL_TRACES_SAMPLER_ARG=always_off using version 0.44b0, then determine whether the documented expectation or the implementation should change. Done means the behavior and documentation agree about whether spans reach the collector.