Update employee_advance.py

https://github.com/frappe/erpnext/issues/13694
Cancel of  already paid "Expense Claim" gives error IntegrityError: (1048, u"Column 'claimed_amount' cannot be null")
Sol: claimed_amount should be flt
diff --git a/erpnext/hr/doctype/employee_advance/employee_advance.py b/erpnext/hr/doctype/employee_advance/employee_advance.py
index 6f550bc..ee0cb83 100644
--- a/erpnext/hr/doctype/employee_advance/employee_advance.py
+++ b/erpnext/hr/doctype/employee_advance/employee_advance.py
@@ -69,7 +69,7 @@
 			where employee_advance = %s and docstatus=1 and allocated_amount > 0
 		""", self.name)[0][0]
 
-		frappe.db.set_value("Employee Advance", self.name, "claimed_amount", claimed_amount)
+		frappe.db.set_value("Employee Advance", self.name, "claimed_amount", flt(claimed_amount))
 
 @frappe.whitelist()
 def get_due_advance_amount(employee, posting_date):
@@ -109,4 +109,4 @@
 		"account_type": payment_account.account_type
 	})
 
-	return je.as_dict()
\ No newline at end of file
+	return je.as_dict()