Only show the reset button if there are messages

templates/main.php

@@ -72,7 +72,7 @@ use \OCA\OcSms\Lib\CountryCodes;
 					<option value="0"><?php p($l->t('Disable'));?></option>
 				</select>
 			</div>
-            <div>
+            <div v-if="!isContactListEmpty()">
                 <button class="crit-button primary" v-on:click="wipeAllMessages();">Reset all messages</button>
             </div>
 		</div> <!-- app-settings-content -->