Deprecating OpenCensus compatibility requirements

On June 12, 2026, the OpenTelemetry Specification project merged PR #5138 , deprecating OpenCensus compatibility requirements in the specification. This change updates the specification to match where the ecosystem already is: OpenCensus has been archived since July 31, 2023 , and the OpenTelemetry shims for OpenCensus have provided a stable migration bridge for more than three years. This is a deprecation of specification requirements, not an immediate removal of compatibility material and not a requirement to remove existing shim artifacts right away.