[FIX] ir_model: stop crashing _prepare_update

If the field being checked in _prepare_update hasn't been loaded yet we
should skip it to avoid a KeyError.

OPW-1871180
OPW-1872236

odoo/addons/base/ir/ir_model.py

@@ -549,7 +549,11 @@ class IrModelFields(models.Model):
         failed_dependencies = []
         for rec in self:
             model = self.env[rec.model]
-            field = model._fields[rec.name]
+            if rec.name in model._fields:
+                field = model._fields[rec.name]
+            else:
+                # field hasn't been loaded (yet?)
+                continue
             for dependant, path in model._field_triggers.get(field, ()):
                 if dependant.manual:
                     failed_dependencies.append((field, dependant))