The goal of this commit is to allow relatedFields to be added to a one2many
field using a sub-view.
Before this commit, if an x2many custom contains a sub-view and relatedFields,
we ignore the sub-view and use only the relatedFields.
Now we're going to add the relatedFields to the fields/activeFields
defined in the sub-view.
Use case:
Created a custom x2many field dependent on the 'display_name' of
a many2one field that should not be present in the sub-view. For example,
to simulate a groupBy on this many2one field.
closesodoo/odoo#132351
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>