Fix timeline activities display (#16880)

Fixes https://github.com/twentyhq/twenty/issues/16809

# Introduction
Front was expected timeline activities field to be relation and not
morph relation

Also fixed the new v2 workspace creation that had a bug in the
createStandardRelation util ( it's not in production yet so everything's
fine )

packages/twenty-front/src/modules/activities/timeline-activities/hooks/useTimelineActivities.ts

@@ -31,8 +31,12 @@ export const useTimelineActivities = (
 
   const hasTimelineActivityField = timelineActivityMetadata.fields.some(
     (field) =>
-      field.relation?.targetObjectMetadata?.nameSingular ===
-      targetableObject.targetObjectNameSingular,
+      isDefined(field.morphRelations) &&
+      field.morphRelations.some(
+        (morphRelation) =>
+          morphRelation.targetObjectMetadata?.nameSingular ===
+          targetableObject.targetObjectNameSingular,
+      ),
   );
 
   const { recordGqlFields: depthOneRecordGqlFields } =