Fix timeline activity missing updated fields (#5854)

## Before
<img width="883" alt="Screenshot 2024-06-13 at 14 48 05"
src="https://github.com/twentyhq/twenty/assets/1834158/0e72ead1-2d59-4ee3-af3b-dfdd593b7f2e">


## After
<img width="908" alt="Screenshot 2024-06-13 at 14 48 14"
src="https://github.com/twentyhq/twenty/assets/1834158/00e32ddf-e40d-4cc9-a80a-9f5b76bd377a">

packages/twenty-server/src/modules/timeline/repositiories/timeline-activity.repository.ts

@@ -35,6 +35,17 @@ export class TimelineActivityRepository {
       workspaceId,
     );
 
+    // If the diff is empty, we don't need to insert or update an activity
+    // this should be handled differently, events should not be triggered when we will use proper DB events.
+    const isDiffEmpty =
+      properties.diff !== null &&
+      properties.diff &&
+      Object.keys(properties.diff).length === 0;
+
+    if (isDiffEmpty) {
+      return;
+    }
+
     if (recentTimelineActivity.length !== 0) {
       const newProps = objectRecordDiffMerge(
         recentTimelineActivity[0].properties,