Hide bridge aspect in context bridge toString

[anuraaga]

Currently we just print out all the contents of our bridged context, including implementation details like the otel-context. It probably makes sense to just print out the "resolved context" so that adding the javaagent has a same Context.toString as without the javaagent (with the expection of extra fields possibly added to the context by instrumentation itself though).

[trask]

Closing, can revisit later if anyone has renewed interest.