AngularJS is not showing data in Hindi language

I am trying to fetch MYSQL database data in AngularJS, Data is in hindi language. Database collation set to ‘utf8_unicode_ci’.

<div ng-controller="postController" ng-init="display_data()">
    <table class="table table-bordered">
        <tr>
            <th>Post id </th>
            <th>Post Title</th>
            <th>Post Details</th>
            <th>Post Status</th>
        </tr>
        <tr ng-repeat="x in posts" >
            <td>{{x.postId}}</td>
            <td>{{x.postTitle}}</td>
            <td>{{x.postDetails}}</td>
            <td>{{x.postStatus}}</td>
        </tr>
    </table>
</div>
<script>
    var app = angular.module("concept", []);
    app.controller("postController", function ($scope, $http) {
        $scope.display_data = function () {
            $http({
                method: 'GET',
                url: 'getPost.php'
            }).then(function (post) {
                $scope.posts = post.data;
            }, function (error) {
                alert("Something went wrong!!");
            });
        }
    });
</script>

No error in console

Here is php code:

<?php 
header('Content-Type: text/html; charset=utf-8');
$conn = mysqli_connect("localhost","root","","concept") or die(mysqli_error()) ; 
$output = array();

$query = "SELECT * FROM userpost";

$result=mysqli_query($conn,$query);
if(mysqli_num_rows($result)>0)
{
    while($row = mysqli_fetch_array($result))
    {
        $output[] = $row;
    }
    echo json_encode($output);
}

?>

code running on local server.

Source: AngularJS