nixos/zfs: enable requestEncryptionCredentials by default

Since zfsStable now supports encryption, it no longer makes sense to set
the default based on whether we're using zfsUnstable

nixos/modules/tasks/filesystems/zfs.nix

@@ -179,10 +179,9 @@ in
 
       requestEncryptionCredentials = mkOption {
         type = types.bool;
-        default = config.boot.zfs.enableUnstable;
+        default = true;
         description = ''
           Request encryption keys or passwords for all encrypted datasets on import.
-          Dataset encryption is only supported in zfsUnstable at the moment.
           For root pools the encryption key can be supplied via both an
           interactive prompt (keylocation=prompt) and from a file
           (keylocation=file://). Note that for data pools the encryption key can