Follow-up of #20810

Once https://github.com/micrometer-metrics/micrometer/issues/1965 is fixed we should remove the code that we've duplicated for the time being.

Comment From: snicoll

I've removed the duplication now that there is a public API we can use. Unfortunately I've discovered a problem that is making one of our test fails. I've suggested a fix https://github.com/micrometer-metrics/micrometer/pull/1979