Azure DevOps Issue: Work item type Test Case cannot be disabled. Disabling test work item types is not allowed.
Solution : By Default TestCase workitem cannot be disabled. And along with it TestSuites/TestPlan can’t be also disabled. This is a default feature of Azure DevOps and there are no customizations.Even if you remove or turn off Azure TestPlans from the Project, the testcase option would be still visible as it can’t be disabled