Fix storybook / chromatic tests flakyness and integration tests (#11687)

## Storybook flakyness

### Actor Display image flakyness

<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/875c0738-5e31-4aba-9231-4ba5f78d1355"
/>

**Fix:** stop using a random usage

### Task Groups broken

<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/c67e47a1-a027-43f1-9601-68d61a8052b4"
/>

**Fix:** add missing TabListComponentInstance

## Flaky dates

Add https://github.com/k35o/storybook-addon-mock-date

## Integration tests

Fix broken tests due to relation refactoring

packages/twenty-server/src/engine/metadata-modules/field-metadata/field-metadata.resolver.ts

@@ -161,12 +161,6 @@ export class FieldMetadataResolver {
       throw new ValidationError("Active fields can't be deleted");
     }
 
-    if (fieldMetadata.type === FieldMetadataType.RELATION) {
-      throw new ValidationError(
-        "Relation fields can't be deleted, you need to delete the RelationMetadata instead",
-      );
-    }
-
     try {
       return await this.fieldMetadataService.deleteOneField(input, workspaceId);
     } catch (error) {