Integer Blueprint variables reset the Bitmask Enum setting when the Editor closes

User created Bitmask flag Enumerators are not correctly stored and retrieved from Blueprint Integer variable settings. When the Editor is restarted the value of the Integer's Bitmask Enum is set to None. When using a premade Enum such as EAnimAssetCurveFlags, the value will be set to the premade enum upon restart.

This issue was reported and tested in 4.21.2 (CL-4753647). This was reproduced in 4.20.3 (CL-4369336), 4.22 (CL-5159901), and Main 4.23 (CL-5236305)

1. Open the UE4 Editor and create a Blank project
2. Create a new Enumeration, open it and enable Bitmask Flags
3. Create a new Actor Blueprint and add an Integer variable
4. In the Interger variable enable Bitmask and change the Bitmask Enum to the one that was created
5. Save and restart the Editor
6. Reopen the Actor Blueprint and select the Interger

Results: Bitmask Enum is set to none

Expected: Bitmask Enum should be the Enum created