Numeric enumerations should use AllowedValues

Part 3: CSDL states that enumeration values are sorted and compared using their numeric value because it allows synonym symbolic names with the same numeric value.

Part 3: CSDL also only allows symbolic values in annotations.

JSON Format on the other hand states that the symbolic name, represented as a string, is preferred.

This makes life unnecessarily complicated for clients to evaluate conditional annotation expressions based on enums as they can't compare enum values in annotations and payloads without internally translating them into numeric values, which they can only know after reading vocabulary files.