Provide function pointers in logger as catch call check

[ThomsonTan]

This is follow up for below comment. It could be benefit if the the API Logger can have a place (like function pointer member) for SDK/exporter to register its its own Enabled check, in case the fast check based on severity failed.

https://github.com/open-telemetry/opentelemetry-cpp/pull/2094#discussion_r1169379188

[github-actions[bot]]

This issue was marked as stale due to lack of activity.