fix(sla): 'doctype' is not defined (#26982)

diff --git a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
index eb9fa12..083bde9 100644
--- a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
+++ b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
@@ -220,7 +220,7 @@
 		return
 
 	filters = [
-		["Service Level Agreement", "document_type", "=", doctype],
+		["Service Level Agreement", "document_type", "=", doc.get('doctype')],
 		["Service Level Agreement", "enabled", "=", 1]
 	]