Before this commit, the reference of a validation transaction followed this format: “validation-20220222072710”, which did not match the standard format for refund transactions (”R-S000001”). Moreover, some providers limit the length of transaction references which forced us to truncate the quite long reference. With this commit, future validation transactions will have a reference of the format: “V-20220222072710”. task-2830826 closes odoo/odoo#94921 Related: odoo/enterprise#29076 Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>