Fix arguments order for implode and remove error messages

Problem/Motivation

1) Error for view preview and PHP 8 :

TypeError: implode(): Argument #2 ($array) must be of type ?array, string given in implode() (line 22 of web/modules/contrib/jsonapi_views/jsonapi_views.module)

See https://www.php.net/manual/en/function.implode.php
Since PHP 8.0.0 : Passing the separator after the array is no longer supported.

2) Warnings when you valide a preview with filter :

Warning: Undefined array key "sort_by" in jsonapi_views_views_preview_info_alter() (line 27 of modules/contrib/jsonapi_views/jsonapi_views.module).
Warning: Undefined array key "sort_order" in jsonapi_views_views_preview_info_alter() (line 30 of modules/contrib/jsonapi_views/jsonapi_views.module).

Steps to reproduce

1) Edit a view and see log.

2) add exposed filter fill the input and click Preview.

Proposed resolution

Change implode arguments order, and test existence of array keys.