Customgrouping 1 is accidently used for SDK value

[EnessenE]

java/blob/master/src/main/java/com/cm/text/models/Message.java#L36
Wrong customgrouping is being used for the text-sdk-java label. This should be customgrouping3 as seen in the dotnet SDK https://github.com/cmdotcom/text-sdk-dotnet/blob/ead36bf5ccbf2ab28586b0f5b27cf216d7c87df3/CM.Text/BusinessMessaging/MessageBuilder.cs#L37

[malcos]

It is nowhere specified what are the default values for those. And using that very same logic, all fields should be empty, no default values should be set if you ask me.