chore: upgrade to TB 9.3.12 (24.7) (#7607) (#7609)

Co-authored-by: Zhe Sun <31067185+ZheSun88@users.noreply.github.com>

Author: vaadin-bot

versions.json

@@ -562,7 +562,7 @@
             "pro": true
         },
         "vaadin-testbench": {
-            "javaVersion": "9.3.11",
+            "javaVersion": "9.3.12",
             "pro": true
         }
     }