Custom field Optimizer should have the options to rescan for a single custom field

When showing the custom fields with the option to change, it would be good to have the option to re-scan the database for just this single field.

Depending on the original scan timing and other changes executed the data/configuration could be changed.

The goal is to prevent losing data or configuration due to the scan not reflecting the current state of the contexts and their usage.

This is similar to JRASERVER-76265 however due to timing a full scan might not be needed.