[Improvement][Master] Initialize WorkflowGraph/WorkflowExecutionGraph when `WorkflowStartLifecycleEvent` fired.

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/dolphinscheduler/issues?q=is%3Aissue) and found no similar feature requirement.

### Description

It's better not initialize WorkflowGraph/WorkflowExecutionGraph when handle command, and initialize these when start event fired.
The advantage is that we can reduce transaction time when processing commands, and once initialize graph failed, we can trigger a workflow instance failure event.

### Are you willing to submit a PR?

- [x] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)