## What changes were proposed in this pull request?

The scal() and creation of newCenter vector is done in the driver, after a collectAsMap operation while it could be done in the distributed RDD.
This PR moves this code before the collectAsMap for more efficiency

## How was this patch tested?

This was tested manually by running the KMeansExample and verifying that the new code ran without error and gave same output as before.

Author: dardelet <guillaumegorp@gmail.com>
Author: Guillaume Dardelet <dardelet@users.noreply.github.com>

Closes #18491 from dardelet/move-center-calculation-to-distributed-map-kmean.