[FIX] product : Decimal Accuracy for Value Price Extra

Issue :
'Value Price Extra' cannot have the N-digit Decimal Accuracy configuration but 'Product Price' can.
Solve :
Added field_digits to views
opw-2674006

closes odoo/odoo#79277

X-original-commit: fb372fb6
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>