Fix Multi-level Child Epics UI Accessible in Premium When Feature is Ultimate-Only

What does this MR do and why?

Resolves both #525856 (closed) and #517599 (closed). Hides parent widget on epic and issue creation in the modal based on the license

• For epic, parent widget is only shown on Ultimate
• For issues, parent widget is hidden on Free license

Screenshots or screen recordings

Issues on Ultimate	Issues on Free

Same goes for Epics on Ultimate vs Epics on Premium and below

How to set up and validate locally

Enable work_item_planning_view to view the creation modal globally (available via + in the sidebar navigation)

1. Make sure that the Parent widget is visible in epic and issue creation modal on Ultimate license.
2. Make sure Parent widget is hidden from epic creation modal on Premium license and below.
3. Make sure Parent widget is hidden in issue creation modal on Free license.

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 #525856 (closed)