Micrometer bridge: interpret no SLO config as no buckets advice

[mateuszrzeszutek]

Resolves #8841 (?)

cc @zeitlinger

This implements my idea from the issue:

By default Micrometer Timers have no buckets at all, unless you configure serviceLevelObjectives via the builder. Perhaps what we should do is preserve that behavior in the bridge as well -- and pass an empty bucket list if the user has not explicitly configured them via Micrometer API. At least it would be consistent with how "plain" Micrometer behaves.

[zeitlinger]

Thanks @mateuszrzeszutek for taking the time to explain - I also approve 😄

[mateuszrzeszutek]

You're welcome! I definitely agree that the number of layers and components here might get confusing

[trask]

I also approve 😄

❤️

even though you're not an official approver, you can still hit the approve button, we definitely factor in non-green checkmarks when merging