Fix permissions on deleteMissing=false (#2532)

src/Discord.Net.Interactions/Utilities/ApplicationCommandRestUtil.cs

@@ -227,7 +227,7 @@ namespace Discord.Interactions
                     Name = command.Name,
                     Description = command.Description,
                     IsDefaultPermission = command.IsDefaultPermission,
-                    DefaultMemberPermissions = (GuildPermission)command.DefaultMemberPermissions.RawValue,
+                    DefaultMemberPermissions = command.DefaultMemberPermissions.RawValue == 0 ? new Optional<GuildPermission>() : (GuildPermission)command.DefaultMemberPermissions.RawValue,
                     IsDMEnabled = command.IsEnabledInDm,
                     IsNsfw = command.IsNsfw,
                     Options = command.Options?.Select(x => x.ToApplicationCommandOptionProps())?.ToList() ?? Optional<List<ApplicationCommandOptionProperties>>.Unspecified,
@@ -238,7 +238,7 @@ namespace Discord.Interactions
                 {
                     Name = command.Name,
                     IsDefaultPermission = command.IsDefaultPermission,
-                    DefaultMemberPermissions = (GuildPermission)command.DefaultMemberPermissions.RawValue,
+                    DefaultMemberPermissions = command.DefaultMemberPermissions.RawValue == 0 ? new Optional<GuildPermission>() : (GuildPermission)command.DefaultMemberPermissions.RawValue,
                     IsNsfw = command.IsNsfw,
                     IsDMEnabled = command.IsEnabledInDm,
                     NameLocalizations = command.NameLocalizations?.ToImmutableDictionary() ?? ImmutableDictionary<string, string>.Empty,
@@ -248,7 +248,7 @@ namespace Discord.Interactions
                 {
                     Name = command.Name,
                     IsDefaultPermission = command.IsDefaultPermission,
-                    DefaultMemberPermissions = (GuildPermission)command.DefaultMemberPermissions.RawValue,
+                    DefaultMemberPermissions = command.DefaultMemberPermissions.RawValue == 0 ? new Optional<GuildPermission>() : (GuildPermission)command.DefaultMemberPermissions.RawValue,
                     IsNsfw = command.IsNsfw,
                     IsDMEnabled = command.IsEnabledInDm,
                     NameLocalizations = command.NameLocalizations?.ToImmutableDictionary() ?? ImmutableDictionary<string, string>.Empty,