[improve] Avoid each time no change submit will create a new version

Currently, each time submit code from python api to dolphinscheduler, a new version will be add even though do not change any task, workflow, and relation. It is better to find a way check whether there are any models change to judge add version or not

No file or test is named. Start by tracing the Python API submit path and how task, workflow, and relation models are compared or persisted; done means submitting an unchanged definition does not create a new version, while a model change still does.

Written by the indexing model from the issue text.