JS: remove dependency on jQuery and fix code quality

Problem/Motivation

If possible, rewrite JS code to remove dependency on jQuery and properly implements once and usage of the context in behaviors.

Also fix code quality, https://git.drupalcode.org/project/gin_lb/-/jobs/784903:

/builds/project/gin_lb/web/modules/custom/gin_lb/assets/js/gin_lb_offcanvas.js
  33:57  warning  Too many nested callbacks (4). Maximum allowed is 3  max-nested-callbacks
✖ 1 problem (0 errors, 1 warning)