In the normal course of saving-action, readonly fields are stripped
out when sending data to the server. The SSF would reuse the same code
when "saving" O2M lines to the parent record however that is not
correct and would lead to misbehaving views as readonly (non-stored)
fields used as "transients" (storing data within the extent of a
record's edition session) would not behave properly.
Fix by overriding the O2M Form's save so that readonly fields are
kept and stored in the parent record.
Closes#23620
Laurent Smet
34c7fe2e77