Add tests that EVENT is stored in DB and has right values in userId.

backend/src/graphql/resolver/ContributionResolver.test.ts

@@ -815,6 +815,15 @@ describe('ContributionResolver', () => {
           })
           expect(isDenied).toBeTruthy()
         })
+
+        it('stores the admin deny contribution event in the database', async () => {
+          await expect(EventProtocol.find()).resolves.toContainEqual(
+            expect.objectContaining({
+              type: EventProtocolType.ADMIN_CONTRIBUTION_DENY,
+              userId: admin.id,
+            }),
+          )
+        })
       })
     })
   })

backend/src/graphql/resolver/ContributionResolver.ts

@@ -732,7 +732,7 @@ export class ContributionResolver {
 
     const event = new Event()
     const eventAdminContributionDeny = new EventAdminContributionDeny()
-    eventAdminContributionDeny.userId = contributionToUpdate.userId
+    eventAdminContributionDeny.userId = moderator.id
     eventAdminContributionDeny.amount = contributionToUpdate.amount
     eventAdminContributionDeny.contributionId = contributionToUpdate.id
     await writeEvent(event.setEventAdminContributionDeny(eventAdminContributionDeny))