Reset Tab Page Layout (#19453)

## Context
- Add "Reset to default" for page layout tabs and widgets — backend
mutation resets overrides, reactivates deactivated children, and deletes
custom children
- Fix override write bug where mutating an overridable property (e.g.
widget title) on a standard-app entity incorrectly overwrote the base
column instead of writing to the overrides JSONB —
PageLayoutUpdateService now uses resolveFlatEntityOverridableProperties
for accurate diffing and routes properties through
sanitizeOverridableEntityInput
- Deprecate isOverridden - We need more time to think about this
feature. Currently this adds too much complexity for a very small
benefit



https://github.com/user-attachments/assets/a84546c8-1e15-4d9e-a489-0825cf8b8ed2

packages/twenty-server/src/engine/metadata-modules/view-field/utils/from-flat-view-field-to-view-field-dto.util.ts

@@ -1,17 +1,15 @@
-import { isDefined } from 'twenty-shared/utils';
-
 import { type FlatViewField } from 'src/engine/metadata-modules/flat-view-field/types/flat-view-field.type';
 import { type ViewFieldDTO } from 'src/engine/metadata-modules/view-field/dtos/view-field.dto';
 
 export const fromFlatViewFieldToViewFieldDto = (
   flatViewField: FlatViewField,
 ): ViewFieldDTO => {
-  const { createdAt, updatedAt, deletedAt, ...rest } = flatViewField;
+  const { createdAt, updatedAt, deletedAt, overrides, ...rest } = flatViewField;
 
   return {
     ...rest,
-    isOverridden:
-      isDefined(rest.overrides) && Object.keys(rest.overrides).length > 0,
+    ...(overrides ?? {}),
+    isOverridden: false,
     createdAt: new Date(createdAt),
     updatedAt: new Date(updatedAt),
     deletedAt: deletedAt ? new Date(deletedAt) : null,