Move imports in transport_nsw component

[exxamalte]

Breaking Change:

Description:

Moved import from function to top-level as requested in #27284

Related issue (if applicable): #27284

Pull request with documentation for home-assistant.io (if applicable): n/a

Example entry for configuration.yaml (if applicable): n/a

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.