Consider any field of new record as loaded

It is needed to trigger the validation of all the fields to set default value
thanks to the domain inversion.

Closes #14004

sao/src/model.js

@@ -1367,6 +1367,9 @@
             }
         },
         get_loaded: function(fields) {
+            if (this.id < 0) {
+                return true;
+            }
             if (!fields) {
                 fields = Object.keys(this.model.fields);
             }

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

@@ -303,6 +303,8 @@ class Record:
             self.reload(fields)
 
     def get_loaded(self, fields=None):
+        if self.id < 0:
+            return True
         if fields is None:
             fields = self.group.fields.keys()
         return set(fields) <= (self._loaded | set(self.modified_fields))