[otelarrowreceiver] Avoid one unnecessary span error at stream EOF

[jmacd]

Description: We have been using the OTel-Arrow components in production and begun to monitor the component's health using span data. There are spans coming from otelgrpc instrumentation and there are explicit spans in both components.

This adds a new test that exercises multiple streams between the exporter and receiver components. At the end of the test, it checks for no span errors, with one exception discussed in open-telemetry/opentelemetry-go-contrib#2644. We will not modify the logic of these components to avoid stream cancelation, we will lobby for stream cancelation not to register as span errors.

The receiver is modified to avoid setting Span errors for EOF and Cancelation following its existing logic for setting log severity for the same condition. As a result, the otel_arrow_stream_inflight span will not show errors for the final Recv() as a stream shuts down.

Link to tracking Issue: Part of open-telemetry/otel-arrow#227.

Testing: A new test is added.