Check switching of types

What does this MR do and why?

Although work items type is not allowed to be changed (yet), because WorkItem is internally an Issue and we allow switching issue_type for an issue through Issue API, it's still possible to change work item's type through Issue API.

This MR restricts set of issue types which user can switch between. The purpose of this change is to keep existing functionality when user can switch between issue, incident and test cases, while restricting this change of type for other newer work item types (work items inherit from issues).

Related to #385256 (closed)

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How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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