Add traceparent header support for sentry-native #1350
Description
This allows trace propagation to work when sentry-client SDKs communicate with otel instrumented backends.
Develop Docs:
https://develop.sentry.dev/sdk/telemetry/traces/#propagatetraceparent
https://develop.sentry.dev/sdk/telemetry/traces/distributed-tracing/#w3c-trace-context-header