Description

Resolves #8722

Several problems:

1. The OpenTelemetry tracing provider library lacked an implementation of DataPropagationProvider. As a result, OTel-based tracing information was never propagated via context.
2. The TracingObserver registered only the SpanContext in the context, not also the Span and Tracer. The existing Jaeger data propagation provider and the new one for OTel need to retrieve the Span from the context so we can re-establish that span as the active span during a runInContext.
3. The original Jaeger data propagation provider propagateData method incorrectly used the current span rather than the span captured in the JaegerContext object earlier. The analogous code in the new OpenTelemetryDataPropagationProvider uses the saved context instead and the analogous Jaeger type now extends that OTel implementation.

Because Jaeger relies on OTel, the Jaeger and the OTel propagation providers are virtually identical. This PR makes the Jaeger one a subclass of the new OTel one to avoid duplicating the code.

Documentation

Bug fix; no doc impact.