chore: upgrade to TB 9.3.12 (24.7) (#7607)

Author: ZheSun88

versions.json

@@ -569,7 +569,7 @@
             "pro": true
         },
         "vaadin-testbench": {
-            "javaVersion": "9.3.11",
+            "javaVersion": "9.3.12",
             "pro": true
         }
     }