chore: mark trace exporters private to prevent publish

[dyladan]

This will prevent the exporters from being released when a stable release is cut. They can then be moved to experimental.

[codecov]

Codecov Report

Merging #2836 (c0546e4) into main (4ca2d89) will not change coverage.
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[rauno56]

They can then be moved to experimental.
"They"?

Can you elaborate why we want to prevent publishing them?

[dyladan]

They can then be moved to experimental.
"They"?

Can you elaborate why we want to prevent publishing them?

Discussed in slack but copying into the thread for others:

JSON format is the root of it. JSON format is not stable, therefore JSON exporter cannot be released stable. protobuf and gRPC exporters depend on JSON exporter to do the transformation logic. Do not want to release a stable exporter which depends on an experimental exporter.