remove X-B3-ParentSpanId for B3 propagator as per OpenTelemetry Specification#2237

owais merged 6 commits intoopen-telemetry:mainopen-telemetry/opentelemetry-python:mainfrom

open-o11y:otel-spec-B3-propagator-B3-ParentSpanIDopen-o11y/opentelemetry-python:otel-spec-B3-propagator-B3-ParentSpanIDCopy head branch name to clipboard