fix: opportunity link is missign from customer (#28110)

diff --git a/erpnext/crm/doctype/opportunity/opportunity.py b/erpnext/crm/doctype/opportunity/opportunity.py
index 55e0efa..0e469ac 100644
--- a/erpnext/crm/doctype/opportunity/opportunity.py
+++ b/erpnext/crm/doctype/opportunity/opportunity.py
@@ -314,6 +314,8 @@
 @frappe.whitelist()
 def make_customer(source_name, target_doc=None):
 	def set_missing_values(source, target):
+		target.opportunity_name = source.name
+
 		if source.opportunity_from == "Lead":
 			target.lead_name = source.party_name