[MINOR] improvement(dashboard): Support sortable for totalSize column…

… of applicationPage within dashboard webui (#2224)

### What changes were proposed in this pull request?

Support sortable for totalSize column of applicationPage within dashboard webui

### Why are the changes needed?

- Easy to find out the biggest application.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Tested Localy

<img width="136" alt="image" src="https://github.com/user-attachments/assets/f3f14951-985d-4f8c-ae93-c6ce28ee82c5">

dashboard/src/main/webapp/src/pages/ApplicationPage.vue

@@ -116,6 +116,7 @@
             label="TotalSize"
             min-width="180"
             :formatter="memFormatter"
+            sortable
         />
       </el-table>
     </div>