Fix position calculations -- favorites (#9202)

Co-authored-by: Weiko <corentin@twenty.com>

packages/twenty-front/src/modules/favorites/utils/calculateNewPosition.ts

@@ -10,18 +10,19 @@ export const calculateNewPosition = ({
   items,
 }: CalculateNewPositionParams): number => {
   if (destinationIndex === 0) {
-    return items[0].position / 2;
+    return items[0].position - 1;
   }
 
-  if (destinationIndex === items.length - 1) {
-    return items[destinationIndex - 1].position + 1;
+  if (destinationIndex === items.length) {
+    return items[items.length - 1].position + 1;
   }
 
   if (destinationIndex > sourceIndex) {
     return (
-      (items[destinationIndex + 1].position +
+      items[destinationIndex].position +
+      (items[destinationIndex - 1].position -
         items[destinationIndex].position) /
-      2
+        2
     );
   }