Show milestone due date on issue board columns

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What does this MR do and why?

Working from an issue board with milestone columns, we're getting confused about the due dates for each of the milestones, and hovering over the milestone just repeats the milestone name. This merge request has the functionality to show the milestone preview popover when hovering the milestone name in the column header.

References

Related Issue - #25595

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Go to Issue boards > Click on + New List > Select Milestone from the Scope options > Select a milestone > Click Add to board
2. Hover over the new column title.

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #25595