TypedConstant.ToCSharpString/ToVisualBasicString should exclude bitwise or value of 0

Version Used: 4.7.0

Steps to Reproduce:

1. Define FlagEnum:

[Flags]
public enum FlagEnum
{
    None = 0,
    Flag1 = 1,
    Flag2 = 2,
    Flag3 = 4,
}

2. Get an instance of TypedConstant with value FlagEnum.Flag1 | FlagEnum.Flag3;
3. Call TypedConstant.ToCSharpString()/ToVisualBasicString().

Expected Behavior: Returns FlagEnum.Flag1 | FlagEnum.Flag3 in C#, or FlagEnum.Flag1 Or FlagEnum.Flag3 in VisualBasic.

Actual Behavior: Returns FlagsEnum.None | FlagEnum.Flag1 | FlagEnum.Flag3 in C#, or FlagEnum.None Or FlagEnum.Flag1 Or FlagEnum.Flag3 in VisualBasic.