[Streaming][minor] Remove additional quote and unneeded imports

[jerryshao]

No description provided.

[SparkQA]

Test build #30399 has finished for PR 5540 at commit ebaa646.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.
• This patch does not change any dependencies.

[srowen]

That's fine. I think this is below the threshold of being worth opening a PR, since it is a trivial improvement, and still takes, you know, probably half an hour of time added up over all the people that will look at this, Jenkins cycles, commit in the commit log, etc. Tiny cost but doesn't seem worth it given how incredibly busy this is. Your time would be better spent reviewing PRs or working on larger issues.