Refactor Expense Claim (#12883)

* patch for custom workflow

* deleted field approval_status

* replaced approval_status with workflow_state

* updated test cases

* validation to check expense approver

* check if workflow_state_name already exists

* fixes

* modified notifications.py

* removed field exp_approval and modified test cases
diff --git a/erpnext/startup/notifications.py b/erpnext/startup/notifications.py
index 690ccf0..3ab2be4 100644
--- a/erpnext/startup/notifications.py
+++ b/erpnext/startup/notifications.py
@@ -30,7 +30,7 @@
 			},
 			"Payment Entry": {"docstatus": 0},
 			"Leave Application": {"docstatus": 0},
-			"Expense Claim": {"approval_status": "Draft"},
+			"Expense Claim": {"docstatus": 0},
 			"Job Applicant": {"status": "Open"},
 			"Delivery Note": {
 				"status": ("not in", ("Completed", "Closed")),