fix(core): Restore workflow ID during execution creation (#8031)

## Summary
Restore workflow ID during execution creation removed by [this
PR](https://github.com/n8n-io/n8n/pull/8002/files#diff-c8cbb62ca9ab2ae45e5f565cd8c63fff6475809a6241ea0b90acc575615224af).
The missing workflow ID, and more generally the fact that `workflow.id`
is optional when it should not be, causes `PermissionChecker.check` to
misreport a credential as inaccessible when it should be accessible.

More generally, start reporting ID-less workflows so we can root them
out and prevent this at type level.

## Related tickets and issues

https://n8nio.slack.com/archives/C035KBDA917/p1702539465555529

packages/cli/test/integration/database/repositories/execution.repository.test.ts

@@ -43,6 +43,7 @@ describe('ExecutionRepository', () => {
 			const executionDataRepo = Container.get(ExecutionDataRepository);
 			const executionData = await executionDataRepo.findOneBy({ executionId });
 			expect(executionData?.workflowData).toEqual({
+				id: workflow.id,
 				connections: workflow.connections,
 				nodes: workflow.nodes,
 				name: workflow.name,