Add properties to select OpenTelemetry's sampler

[mhalbritter]

Right now, we always use a parentBased(traceIdRatioBased) based sampler with a probability read from management.tracing.sampling.probability.

Looking at the documentation, those are the supported samplers:

Known values for OTEL_TRACES_SAMPLER are:

• "always_on": AlwaysOnSampler
• "always_off": AlwaysOffSampler
• "traceidratio": TraceIdRatioBased
• "parentbased_always_on": ParentBased(root=AlwaysOnSampler)
• "parentbased_always_off": ParentBased(root=AlwaysOffSampler)
• "parentbased_traceidratio": ParentBased(root=TraceIdRatioBased)

We could add a new property management.opentelemetry.tracing.sampler. The trace ratio sampler would use management.tracing.sampling.probability.

[mhalbritter]

I noticed this new warning and I suspect it has something to do with the changes from this issue:

2026-03-13T12:35:18.232+01:00  WARN 442662 --- [sb-49583] [           main] [                                                 ] i.o.s.t.s.ParentBasedSamplerBuilder      : TraceIdRatioBasedSampler is being used as a child sampler (root). This configuration is discouraged per the OpenTelemetry specification and may lead to unexpected sampling behavior.

[mhalbritter]

Just a coincidence. This is a bug in OpenTelemetry Java SDK, see open-telemetry/opentelemetry-java#8065. It's fixed in 1.60.0: https://github.com/open-telemetry/opentelemetry-java/releases/tag/v1.60.0

Upgrading my demo project to use 1.60.0 removes the warning.