N°9229 - Modernize search foreign keys code with built in JS tools (#847)

* N°9229 - Modernize search foreign keys code with built in JS tools

* N°9229 - Allow modals to have button id specified

* N°9229 - Remove the modal instead of only destroying it

* N°9229 - Remove dead code

* Update js/searchformforeignkeys.js

* Add robustness to modals button id

js/pages/backoffice/toolbox.js

@@ -332,6 +332,12 @@ CombodoModal._ConvertButtonDefinition = function (aButtonsDefinitions) {
 					class: typeof(element.classes) !== 'undefined' ? element.classes.join(' ') : '',
 					click: element.callback_on_click
 				}
+
+                // id is optional, and we don't want to set it if not defined
+                if (typeof element.id !== 'undefined' && element.id !== null) {
+                    aButton.id = element.id;
+                }
+
 				aConverted.push(aButton);
 			}
 	);