fix ArbitraryTextTypeComponent to restrict on value being empty

in my eyes the restriction on that the value of ArbitraryTextTypeComponent  can't be "" is to strict.
and ComplexTextTypeComponent does not have this restriction.

i have run into this in my plugin when updating the fanciful library. The reason i ran into this is that in order to convert some message into JSON dynamically and not add tons of checks the ability to add empty strings is necessary i hope you will review this change and merge it to the project