🐛 Fix LA retract/feedrate edge case (#25445)

Followup to #25442

Marlin/src/module/stepper.cpp

@@ -2261,6 +2261,8 @@ uint32_t Stepper::block_phase_isr() {
                 DIR_WAIT_AFTER();
               }
             }
+            else
+              la_interval = LA_ADV_NEVER;
           }
         #endif // LIN_ADVANCE