[Feature][python] Remove public call in PythonGateway code

### 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

after #10989 finishes, all functions in PythonGateway just look like https://github.com/apache/dolphinscheduler/blob/7196b125d9a6612f2f175c2190d7758a09d7e0b9/dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/python/PythonGateway.java#L394-L396 and maybe we can find some way not declaire the function in PythonGateway, and directly import this function from python api side, we currently have some simple code in https://github.com/apache/dolphinscheduler/blob/5289b09817396046489b28857ad54a85c5ffddb2/dolphinscheduler-python/pydolphinscheduler/tests/integration/test_java_gateway.py#L40-L53

and maybe we can do some things like that, and maybe at last our PythonGateway will only have https://github.com/apache/dolphinscheduler/blob/7196b125d9a6612f2f175c2190d7758a09d7e0b9/dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/python/PythonGateway.java#L566-L594 content

### Use case

_No response_

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] 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)

Start by reading dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/python/PythonGateway.java, especially the referenced lines 394-396 and 566-594, and the integration coverage in dolphinscheduler-python/pydolphinscheduler/tests/integration/test_java_gateway.py. Compare the current gateway declarations with the existing Python-side import approach. Done means the public gateway calls can be removed while the Python API integration continues to work.

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