PR dashboard: comment on draft PRs

[lmolkova]

I really like how PR dashboard comments on PRs and provides a status / tell which side the ball is on.

What I see is that some contributors create draft PRs and expect them to be reviewed. We never documented that maintainers don't review draft PRs unless they are part of some other change / semconv / spec.

I think it'd be useful for PR dashboard to leave an initial comment on the draft PRs saying it's waiting on author to be finalized and stop there - no additional analysis needed. This would effectively document the etiquette.

[lmolkova]

Turns out we do leave a comment like this (e.g. open-telemetry/opentelemetry-python-genai#479), but maybe something else prevents some of them from getting a comment. E.g. open-telemetry/opentelemetry-python-genai#480 - it's not draft anymore (was for a while), but still no comment.

Or open-telemetry/opentelemetry-python-genai#484 - draft and no comment. Also no workflows have run because they needed an approval and now are stuck because of capacity problem.

[UPDATE] after an hour, the CI jobs have run on both PRs, but no dashboard comment still

[trask]

this will be in the next rollout (currently only java instrumentation is in the canary deployments which gets changes right away)