It is very easy to know the snapshot Isolation State of Database and here is the quick script for the same.
FROM sys.databases s
Upon running above code it will return the results describing the status of the isolation level for your database. Here is the screenshot which describes the same.
Just on a side note, remember that READ COMMITTED SNAPSHOT does optimistic reads and pessimistic writes. Whereas, SNAPSHOT does optimistic reads and optimistic writes. It is recommended that you go for READ COMMITTED SNAPSHOT for most of your application where you want to implement row versioning. Microsoft has a detailed article on this subject over here.
Reference: Pinal Dave (https://blog.sqlauthority.com)