fix: SLA not applied automatically when priority is missing (#24447)

diff --git a/erpnext/support/doctype/issue/issue.py b/erpnext/support/doctype/issue/issue.py
index 02d10a4..62b39cc 100644
--- a/erpnext/support/doctype/issue/issue.py
+++ b/erpnext/support/doctype/issue/issue.py
@@ -214,7 +214,7 @@
 
 	def before_insert(self):
 		if frappe.db.get_single_value("Support Settings", "track_service_level_agreement"):
-			self.set_response_and_resolution_time(priority=self.priority, service_level_agreement=self.service_level_agreement)
+			self.set_response_and_resolution_time()
 
 	def set_response_and_resolution_time(self, priority=None, service_level_agreement=None):
 		service_level_agreement = get_active_service_level_agreement_for(priority=priority,