feat: Support bigger font size in dashboard (#10974)

# Pull Request Template

## Description

Fixes
https://linear.app/chatwoot/issue/CW-4091/accessibility-improvement-support-bigger-font-size-for-the-dashboard

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

### **Loom video**

https://www.loom.com/share/1ab781859fa748a5ad54aacbacd127b4?sid=a7dd9164-a6de-462f-bff7-1b25e9c55b4f

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

app/javascript/dashboard/App.vue

@@ -14,6 +14,7 @@ import WootSnackbarBox from './components/SnackbarContainer.vue';
 import { setColorTheme } from './helper/themeHelper';
 import { isOnOnboardingView } from 'v3/helpers/RouteHelper';
 import { useAccount } from 'dashboard/composables/useAccount';
+import { useFontSize } from 'dashboard/composables/useFontSize';
 import {
   registerSubscription,
   verifyServiceWorkerExistence,
@@ -37,8 +38,15 @@ export default {
     const router = useRouter();
     const store = useStore();
     const { accountId } = useAccount();
+    // Use the font size composable (it automatically sets up the watcher)
+    const { currentFontSize } = useFontSize();
 
-    return { router, store, currentAccountId: accountId };
+    return {
+      router,
+      store,
+      currentAccountId: accountId,
+      currentFontSize,
+    };
   },
   data() {
     return {