fix: reportview average of ints should be float (#26284) (#26288)

(cherry picked from commit 8bd40b3)

Co-authored-by: Ankush Menat <ankush@frappe.io>

frappe/public/js/frappe/ui/group_by/group_by.js

@@ -327,6 +327,9 @@ frappe.ui.GroupBy = class {
 			if (this.aggregate_function === "sum") {
 				docfield.label = __("Sum of {0}", [__(docfield.label, null, docfield.parent)]);
 			} else {
+				if (docfield.fieldtype == "Int") {
+					docfield.fieldtype = "Float"; // average of ints can be a float
+				}
 				docfield.label = __("Average of {0}", [__(docfield.label, null, docfield.parent)]);
 			}
 		}