Skip the validation of the parent field of group

This is required because it can happen that a x2M field will have some records
set through an on_change but if the x2M is not linked to a screen then
exclude_field won't be set.

Closes #14283
(grafted from 1e7411d1bf84cdf75359e1ce9c5f4943fc50ad23)

--HG--
branch : 6.0

sao/src/model.js

@@ -1285,7 +1285,7 @@
                     if (field.description.readonly) {
                         continue;
                     }
-                    if (fname == this.group.exclude_field) {
+                    if ([this.group.exclude_field, this.group.parent_name].includes(fname)) {
                         continue;
                     }
                     if (!field.validate(this, softvalidation, pre_validate)) {

tryton/tryton/gui/window/view_form/model/record.py

@@ -397,7 +397,8 @@ class Record(SignalEvent):
                 continue
             if field.attrs.get('readonly'):
                 continue
-            if field_name == self.group.exclude_field:
+            if field_name in {
+                    self.group.exclude_field, self.group.parent_name}:
                 continue
             if not field.validate(self, softvalidation, pre_validate):
                 res = False