fix: Resolved a copilot suggestion

[Prekshith-Microsoft]

This pull request makes a minor change to the test import statements by removing the unused PlanStatus import from backend.v4.models.models in the test_plan_to_mplan_converter.py file. This helps clean up the code and avoid unnecessary imports.## Purpose

• ...

Does this introduce a breaking change?

• Yes
• No

How to Test

• Get the code

git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install

• Test the code

What to Check

Verify that the following are valid

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