Fix empty space above WI title

What does this MR do and why?

This is a small patch to fix empty space above WI title for Epic work items with subepics enabled and no ancestors.

MR: !157496 (merged)

MR acceptance checklist

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Before	After

How to set up and validate locally

To test this locally, you need to enable WI at group level, so you will have to enable these feature flags namespace_level_work_items (If you are still unable to access work-item page for an epic then enable/disable FF from this list - &11777 )

1. Visit Epics page and try to create a new EPIC(If all relevant FF's are enabled then you should see a modal when you click on New Epic)
2. On visiting an EPIC , you should not see empty space above WI title.