feat: Add conversations summary CSV export (#13110)

# Pull Request Template

## Description

This PR adds support for exporting conversation summary reports as CSV.
Previously, the Conversations report incorrectly showed an option to
download agent reports; this has now been fixed to export
conversation-level data instead.

Fixes
https://linear.app/chatwoot/issue/CW-6176/conversation-reports-export-button-exports-agent-reports-instead

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

### Screenshot
<img width="1859" height="1154" alt="image"
src="https://github.com/user-attachments/assets/419d26f4-fda9-4782-aea6-55ffad0c37ab"
/>



## 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: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/routes/dashboard/settings/reports/Index.vue

@@ -76,14 +76,14 @@ export default {
         businessHours,
       };
     },
-    downloadAgentReports() {
+    downloadConversationReports() {
       const { from, to } = this;
       const fileName = generateFileName({
-        type: 'agent',
+        type: 'conversation',
         to,
         businessHours: this.businessHours,
       });
-      this.$store.dispatch('downloadAgentReports', {
+      this.$store.dispatch('downloadConversationsSummaryReports', {
         from,
         to,
         fileName,
@@ -109,10 +109,10 @@ export default {
 <template>
   <ReportHeader :header-title="$t('REPORT.HEADER')">
     <V4Button
-      :label="$t('REPORT.DOWNLOAD_AGENT_REPORTS')"
+      :label="$t('REPORT.DOWNLOAD_CONVERSATION_REPORTS')"
       icon="i-ph-download-simple"
       size="sm"
-      @click="downloadAgentReports"
+      @click="downloadConversationReports"
     />
   </ReportHeader>
   <div class="flex flex-col gap-3">