[Feature Request] Trim string in monetary custom field

Description

Copying a monetary value from a OCR-ed scanned document sometimes adds leading or trailing spaces. These are easy to miss but prevent the validity check from the custom field. I'd suggest they get trimmed automatically.

Other

I did a quick research and there don't seem to be any currencies delimited by space. There might be spaces between powers of thousand (e.g. 7 654 321) which might get trimmed when adding them via keyboard, but since we store as float, these can be ignored anyways.