fix(organization): filter null organizations in listUserInvitations (#8694)

Co-authored-by: Raihan Sharif <raihansharif.info@gmail.com>

packages/better-auth/src/plugins/organization/adapter.ts

@@ -930,9 +930,9 @@ export const getOrgAdapter = <O extends OrganizationOptions>(
 					organization: true,
 				},
 			});
-			return invitations.map(({ organization, ...inv }) => ({
+			return invitations.filter(Boolean).map(({ organization, ...inv }) => ({
 				...inv,
-				organizationName: organization.name,
+				organizationName: organization?.name,
 			}));
 		},
 		createInvitation: async ({