Work item tree tooltip fix

What does this MR do and why?

This MR fixes the tooltip which remains visible even when we move away from the icon

Screenshots or screen recordings

Before	After
Screen_Recording_2023-04-27_at_2.33.50_PM	Screen_Recording_2023-04-27_at_2.31.56_PM

How to set up and validate locally

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

1. Enable the okrs and work_items_mvc flag

   Feature.enable(:okrs_mvc)
   Feature.enable(:work_items_mvc)

2. Either create an objective/ go to any objective and add children
3. Now hover over the expand/collapse icon and see that the tooltip is not persistent even when we move away from the icon

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.