Rename inteval attribute in mjLROpt to interval.

PiperOrigin-RevId: 509275105
Change-Id: Id7840925f6653ecce2e5ea0790575471de4a0364

Author: saran-t

dm_control/mjcf/schema.xml

@@ -37,7 +37,7 @@
             <attribute name="timeconst" type="float"/>
             <attribute name="timestep" type="float"/>
             <attribute name="inttotal" type="float"/>
-            <attribute name="inteval" type="float"/>
+            <attribute name="interval" type="float"/>
             <attribute name="tolrange" type="float"/>
           </attributes>
         </element>