fix: fallback to stock uom if uom is not defined (#16329)

* [minor] Code cleanup

* fix: remove 'or' condition, won't execute
diff --git a/erpnext/stock/get_item_details.py b/erpnext/stock/get_item_details.py
index 01ee9db..692fe5d 100644
--- a/erpnext/stock/get_item_details.py
+++ b/erpnext/stock/get_item_details.py
@@ -281,7 +281,7 @@
 		out.conversion_factor = 1.0
 	else:
 		out.conversion_factor = args.conversion_factor or \
-			get_conversion_factor(item.item_code, args.uom).get("conversion_factor") or 1.0
+			get_conversion_factor(item.item_code, args.uom).get("conversion_factor")
 
 	args.conversion_factor = out.conversion_factor
 	out.stock_qty = out.qty * out.conversion_factor
@@ -651,7 +651,7 @@
 	if not conversion_factor:
 		stock_uom = frappe.db.get_value("Item", item_code, "stock_uom")
 		conversion_factor = get_uom_conv_factor(uom, stock_uom)
-	return {"conversion_factor": conversion_factor}
+	return {"conversion_factor": conversion_factor or 1.0}
 
 @frappe.whitelist()
 def get_projected_qty(item_code, warehouse):