refactor(pagination): use track by in templates

template/pagination/pager.html

@@ -1,3 +1,3 @@
 <ul class="pager">
-  <li ng-repeat="page in pages" ng-class="{disabled: page.disabled, previous: page.previous, next: page.next}"><a ng-click="selectPage(page.number)">{{page.text}}</a></li>
+  <li ng-repeat="page in pages track by $index" ng-class="{disabled: page.disabled, previous: page.previous, next: page.next}"><a href ng-click="selectPage(page.number)">{{page.text}}</a></li>
 </ul>

template/pagination/pagination.html

@@ -1,3 +1,3 @@
 <ul class="pagination">
-  <li ng-repeat="page in pages" ng-class="{active: page.active, disabled: page.disabled}"><a ng-click="selectPage(page.number)">{{page.text}}</a></li>
+  <li ng-repeat="page in pages track by $index" ng-class="{active: page.active, disabled: page.disabled}"><a href ng-click="selectPage(page.number)">{{page.text}}</a></li>
 </ul>