feat: Rewrite configMixin to a composable (#9921)

# Pull Request Template

## Description

This PR will replace the usage of `configMixin` with the `useConfig`
composable.

**Files updated**
1. dashboard/components/layout/sidebarComponents/SecondaryNavItem.vue
2. dashboard/components/widgets/conversation/MessagesView.vue
3. dashboard/routes/dashboard/settings/inbox/Settings.vue **(Not used)**
4. dashboard/routes/dashboard/settings/inbox/FinishSetup.vue **(Not
used)**
5.
dashboard/routes/dashboard/settings/inbox/settingsPage/CollaboratorsPage.vue
6.
dashboard/routes/dashboard/settings/profile/NotificationPreferences.vue
**(Not used)**
7. dashboard/routes/dashboard/settings/profile/AudioNotifications.vue
**(Not used)**
8. dashboard/routes/dashboard/settings/sla/Index.vue **(Not used)**
9. dashboard/routes/dashboard/settings/account/Index.vue
10. survey/views/Response.vue **(Not used)**

Fixes
https://linear.app/chatwoot/issue/CW-3464/rewrite-configmixin-mixin-to-a-composable

## Type of change

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

## How Has This Been Tested?

Test in the component related pages


## 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/shared/mixins/configMixin.js

@@ -1,20 +0,0 @@
-export default {
-  computed: {
-    hostURL() {
-      return window.chatwootConfig.hostURL;
-    },
-    vapidPublicKey() {
-      return window.chatwootConfig.vapidPublicKey;
-    },
-    enabledLanguages() {
-      return window.chatwootConfig.enabledLanguages;
-    },
-    isEnterprise() {
-      return window.chatwootConfig.isEnterprise === 'true';
-    },
-    enterprisePlanName() {
-      // returns "community" or "enterprise"
-      return window.chatwootConfig?.enterprisePlanName;
-    },
-  },
-};