Removed duplicate translation for the dutch language

Resources/translations/SonataAdminBundle.nl.xliff

@@ -334,19 +334,6 @@
                 <source>btn_preview_decline</source>
                 <target>Afkeuren</target>
             </trans-unit>
-
-            <trans-unit id="btn_preview">
-                <source>btn_preview</source>
-                <target>Voorvertoning</target>
-            </trans-unit>
-            <trans-unit id="btn_preview_approve">
-                <source>btn_preview_approve</source>
-                <target>Goedkeuren</target>
-            </trans-unit>
-            <trans-unit id="btn_preview_decline">
-                <source>btn_preview_decline</source>
-                <target>Afkeuren</target>
-            </trans-unit>
         </body>
     </file>
 </xliff>