Merge pull request #16328 from rohitwaghchaure/fixed_salary_structure_employee_reqd

fix: employee is reqd to preview salary slip from salary structure
diff --git a/erpnext/hr/doctype/salary_structure/salary_structure.js b/erpnext/hr/doctype/salary_structure/salary_structure.js
index 033938d..79d75bf 100755
--- a/erpnext/hr/doctype/salary_structure/salary_structure.js
+++ b/erpnext/hr/doctype/salary_structure/salary_structure.js
@@ -124,6 +124,7 @@
 							"label":__("Employee"),
 							"fieldname":"employee",
 							"fieldtype":"Select",
+							"reqd": true,
 							options: employees
 						}, {
 							fieldname:"fetch",