[pgAdmin4][Patch]: Slickgrid loading issue in Query tool

Hi

*Issue:*
Slick-grid libraries loads when an instance of query tool is opened. But
sometimes it throws exception "jQuery is not defined" and it doesn't opens
up.

*Solution:*
As per my understanding, In *datagrid/index.html* file, we set the order of
loading libraries such as
*require(['jquery', 'pgadmin', 'pgadmin.sqleditor']) *
but it still loads *pgadmin.sqleditor.js* file before *jQuery* for unknown
reason.

To fix this, we load *pgadmin.sqleditor.js* file using *require([],
function(){}) *module loader which ensures that the code within
*function(){}* will be executed when pgadmin.sqleditor.js is loaded.

Please find attache patch.
This issue is fixed by *Ashesh Vashi*.

Thanks,
Surinder Kumar