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/conversation/EmailTranscriptModal.vue

@@ -1,7 +1,7 @@
 <!-- eslint-disable vue/no-mutating-props -->
 <template>
   <woot-modal :show.sync="show" :on-close="onCancel">
-    <div class="h-auto overflow-auto flex flex-col">
+    <div class="flex flex-col h-auto overflow-auto">
       <woot-modal-header
         :header-title="$t('EMAIL_TRANSCRIPT.TITLE')"
         :header-content="$t('EMAIL_TRANSCRIPT.DESC')"
@@ -61,7 +61,7 @@
             </label>
           </div>
         </div>
-        <div class="flex flex-row justify-end gap-2 py-2 px-0 w-full">
+        <div class="flex flex-row justify-end w-full gap-2 px-0 py-2">
           <woot-submit-button
             :button-text="$t('EMAIL_TRANSCRIPT.SUBMIT')"
             :disabled="!isFormValid"
@@ -77,9 +77,8 @@
 
 <script>
 import { required, minLength, email } from 'vuelidate/lib/validators';
-import alertMixin from 'shared/mixins/alertMixin';
+import { useAlert } from 'dashboard/composables';
 export default {
-  mixins: [alertMixin],
   props: {
     show: {
       type: Boolean,
@@ -142,10 +141,10 @@ export default {
           email: this.selectedEmailAddress,
           conversationId: this.currentChat.id,
         });
-        this.showAlert(this.$t('EMAIL_TRANSCRIPT.SEND_EMAIL_SUCCESS'));
+        useAlert(this.$t('EMAIL_TRANSCRIPT.SEND_EMAIL_SUCCESS'));
         this.onCancel();
       } catch (error) {
-        this.showAlert(this.$t('EMAIL_TRANSCRIPT.SEND_EMAIL_ERROR'));
+        useAlert(this.$t('EMAIL_TRANSCRIPT.SEND_EMAIL_ERROR'));
       } finally {
         this.isSubmitting = false;
       }