Support partial sampling mode with OTEL span links/events

[jsumners-nr]

Requires:

• Support OTEL span links #3474
• Support OTEL span events #3476

When the agent sampling mode is configured to reduce the data collected and sent, the information we record from span links and span events needs to be correctly reduced. Our planning doc defines the changes required for the partial trace mode. In short:

• When partial tracing is enabled, keep the intrinsic attributes on a link and drop the agent+user attributes.
• When segments are dropped, we must re-parent the span link to the new parent segment. The id intrinsic attribute of the link must be updated to match the id of the span/segment it was re-parented to.
• Span events must be dropped completely.

[Newrelic-Boomi]

https://new-relic.atlassian.net/browse/NR-500612