[Fix] Pos bugs (#16256)

* Remove hard-coded values

* Fix change pos profile + add campaign

* Test case for coveralls

* Remove unnecessary method
diff --git a/erpnext/accounts/page/pos/pos.js b/erpnext/accounts/page/pos/pos.js
index 91f3711..04c8718 100755
--- a/erpnext/accounts/page/pos/pos.js
+++ b/erpnext/accounts/page/pos/pos.js
@@ -1135,16 +1135,18 @@
 	},
 
 	apply_category: function() {
-		var me = this;
-		category = this.selected_item_group || "All Item Groups";
+		frappe.db.get_value("Item Group", {lft: 1, is_group: 1}, "name", (r) => {
+			category = this.selected_item_group || r.name;
 
-		if(category == 'All Item Groups') {
-			return this.item_data
-		} else {
-			return this.item_data.filter(function(element, index, array){
-				return element.item_group == category;
-			});
-		}
+			if(category == r.name) {
+				return this.item_data
+			} else {
+				return this.item_data.filter(function(element, index, array){
+					return element.item_group == category;
+				});
+			}
+		})
+		
 	},
 
 	bind_items_event: function() {