Endpoints: make sure AtD file is loaded before AtD_get_options is used

[eliorivero]

Changes proposed in this Pull Request:

• make sure AtD file is loaded before AtD_get_options is used
• include files once and don't suppress warnings

To test:

1. disable AtD
2. go to Jetpack > Admin and run this in JS Console

jQuery.ajax( {
    url: 'https://thesite.tld/wp-json/jetpack/v4/settings',
    method: 'POST',
    beforeSend: function ( xhr ) {
        xhr.setRequestHeader( 'X-WP-Nonce', Initial_State.WP_API_nonce );
    },
    data: JSON.stringify( {
        'onpublish': true
    } ),
    contentType: "application/json",
    dataType: "json"
} ).done( function ( response ) {
    console.log( response );
} ).error( function ( error ) {
    console.log( error.responseText );
} );

It should succeed and not crash with an error like

br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function AtD_get_options() in /jetpack/_inc/lib/core-api/class.jetpack-core-api-module-endpoints.php:725

[dereksmart]

🐑