Fix DB error on deduping by criteria when criteria string is too long

When deduping & passing in a long string of contacts as a critieria the length of the cachekey can exceed the table field size, causing a DB error.

I have recorded this as critical as it is a fatal error. However, I acknowledge it is very obscure & only accessible by calling the api in a very specific way. It's all a bit mute as the fix is trivial & safe & I expect to get it resolved quickly