[KYUUBI #7072][FOLLOWUP] Fix engine startup permit grafana pannel unit

### Why are the changes needed?

Followup for #7072
The metrics unit should not be `ms`.

### How was this patch tested?

<img width="569" alt="image" src="https://github.com/user-attachments/assets/df83b003-762d-4ee2-bbe1-c1af55ae9795" />

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #7091 from turboFei/7072_followup.

Closes #7072

d7c4fe4 [Wang, Fei] fix unit

Authored-by: Wang, Fei <fwang12@ebay.com>
Signed-off-by: Wang, Fei <fwang12@ebay.com>

Author: turboFei

grafana/dashboard-template.json

@@ -813,7 +813,7 @@
               }
             ]
           },
-          "unit": "ms"
+          "unit": "none"
         },
         "overrides": []
       },