Use List.get(0) instead of getFirst() for Java 17 compatibility

This module compiles against sourceCompatibility=17, but List.getFirst() was added in Java 21 (SequencedCollection), so it failed to resolve. Replaced both calls with List.get(0) and removed the now-unused local variable.

Author: labkey-martyp

laboratory/src/org/labkey/laboratory/assay/AssayHelper.java

@@ -144,7 +144,6 @@ public Map<String, Object> saveTemplate(User u, Container c, ExpProtocol protoco
             row.put("importMethod", importMethod);
             row.put("json", json.toString());
 
-            List<Map<String,Object>> saved;
             if (templateId == null)
             {
                 BatchValidationException bve = new BatchValidationException();
@@ -154,13 +153,13 @@ public Map<String, Object> saveTemplate(User u, Container c, ExpProtocol protoco
                     throw bve;
                 }
 
-                return rows.getFirst();
+                return rows.get(0);
             }
             else
             {
                 row.put("rowid", templateId);
                 List<Map<String, Object>> rows = ti.getUpdateService().updateRows(u, c, Arrays.asList(row), Arrays.asList(Map.of("rowId", templateId)), null, null);
-                return rows.getFirst();
+                return rows.get(0);
             }
         }
         catch (Exception e)