Fix Epic selection for newly created issues within Issue Boards

What does this MR do?

Fixes two of the following ~bug;

• Creating an Issue from Issue Boards immediately reveals sidebar and there EpicsSelect dropdown caused JS errors for type mismatch.
• Selecting Epics from epics dropdown for this newly created issue sent 0 as Issue ID in request which led to 404 error.

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Closes #32289 (closed)