Change "Native Apps" to "Mattermost Apps" for consistency (#3957)

Change "Native Apps" to "Mattermost Apps" for consistency

webapp/components/admin_console/admin_sidebar.jsx

@@ -646,7 +646,7 @@ export default class AdminSidebar extends React.Component {
                                     title={
                                         <FormattedMessage
                                             id='admin.sidebar.nativeAppLinks'
-                                            defaultMessage='Native App Links'
+                                            defaultMessage='Mattermost App Links'
                                         />
 
                                     }

webapp/components/admin_console/native_app_link_settings.jsx

@@ -38,7 +38,7 @@ export default class NativeAppLinkSettings extends AdminSettings {
             <h3>
                 <FormattedMessage
                     id='admin.customization.nativeAppLinks'
-                    defaultMessage='Native App Links'
+                    defaultMessage='Mattermost App Links'
                 />
             </h3>
         );

webapp/components/navbar_dropdown.jsx

@@ -347,7 +347,7 @@ export default class NavbarDropdown extends React.Component {
                     >
                         <FormattedMessage
                             id='navbar_dropdown.nativeApps'
-                            defaultMessage='Download Native Apps'
+                            defaultMessage='Download Mattermost Apps'
                         />
                     </Link>
                 </li>

webapp/components/sidebar_right_menu.jsx

@@ -331,7 +331,7 @@ export default class SidebarRightMenu extends React.Component {
                         <i className='icon fa fa-mobile'></i>
                         <FormattedMessage
                             id='sidebar_right_menu.nativeApps'
-                            defaultMessage='Download Native Apps'
+                            defaultMessage='Download Mattermost Apps'
                         />
                     </Link>
                 </li>