Gameplay Tag Query Variables Don't Retain Custom Default Values in Custom Structs

Gameplay Tag Query variables in custom structs created via the content browser do not retain custom default values.

Found in 4.23.1 CL# 9631420
Reproduced in 4.24 Preview 4 CL3# 10387632, 4.25 Main CL# 10505752

1. Open a project.
2. Create a custom struct (TestStruct) via the Content Browser.
3. Set the member variable(TestVar) to a Gameplay Tag Query.
4. Set a custom default value for TestVar.
5. Close the TestStruct window.
6. Reopen TestStruct and observe the default value for TestVar.

Result: The default value isn't retained.

Expected: The default value is retained.