feat: Replace alertMixin usage with useAlert (#9793)

# Pull Request Template

## Description

This PR will replace the usage of `alertMixin` from the code base with
the `useAlert` composable.

Fixes
https://linear.app/chatwoot/issue/CW-3462/replace-alertmixin-usage-with-usealert

## Type of change

- [x] Breaking change (fix or feature that would cause existing
functionality not to work as expected)

## How Has This Been Tested?

Please refer this issue description

https://linear.app/chatwoot/issue/CW-3462/replace-alertmixin-usage-with-usealert


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] 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

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/javascript/dashboard/components/widgets/AICTAModal.vue

@@ -40,12 +40,12 @@
 import { required } from 'vuelidate/lib/validators';
 import { mapGetters } from 'vuex';
 import aiMixin from 'dashboard/mixins/aiMixin';
-import alertMixin from 'shared/mixins/alertMixin';
+import { useAlert } from 'dashboard/composables';
 import uiSettingsMixin from 'dashboard/mixins/uiSettings';
 import { OPEN_AI_EVENTS } from 'dashboard/helper/AnalyticsHelper/events';
 
 export default {
-  mixins: [aiMixin, alertMixin, uiSettingsMixin],
+  mixins: [aiMixin, uiSettingsMixin],
   data() {
     return {
       value: '',
@@ -67,7 +67,7 @@ export default {
     },
 
     onDismiss() {
-      this.showAlert(
+      useAlert(
         this.$t('INTEGRATION_SETTINGS.OPEN_AI.CTA_MODAL.DISMISS_MESSAGE')
       );
       this.updateUISettings({
@@ -97,7 +97,7 @@ export default {
         this.alertMessage =
           errorMessage || this.$t('INTEGRATION_APPS.ADD.API.ERROR_MESSAGE');
       } finally {
-        this.showAlert(this.alertMessage);
+        useAlert(this.alertMessage);
       }
     },
     openOpenAIDoc() {