Delete experimental metric view baggage extraction

We have experimental methods to extract a configurable set of keys from baggage and add as metric attributes.

This was a carry over from early metric prototypes. The expectation was that after initial metric stabilization in the spec, someone would champion better integration with baggage and metrics, either codifying or superseding the experimental opentelemetry-java feature.

That never played out.

There was a measurement processor concept, which got derailed.

There's a context scoped attributes concept, the shape of which is still being figured out but is notably not related to baggage.

At this point, we're 4+ years past stabilizing opentelemetry-sdk-metrics. I think its time to delete this experimental feature and follow the spec.

Start in sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/SdkMeterProviderUtil.java, especially the experimental baggage extraction at lines 95-132. Trace its callers and related tests or configuration before removing the feature. Done means the experimental baggage-to-metric-attributes behavior is deleted and the SDK follows the current metrics specification.