fix: Rendering of translations based on the user's locale (#13211)

Previously, translations were generated and resolved purely based on the
account locale. This caused issues in multi-team, multi-region setups
where agents often work in different languages than the account default.

For example, an account might be set to English, while an agent prefers
Spanish. In this setup:
- Translations were always created using the account locale.
- Agents could not view content in their preferred language.
- This did not scale well for global teams.

There was also an issue with locale resolution during rendering, where
the system would incorrectly default to the account locale even when a
more appropriate locale should have been used.

With this update, During rendering, the system first attempts to use the
agent’s locale. If a translation for that locale does not exist, it
falls back to the account locale.


**How to test:**

- Set agent locale to a specific language (e.g., zh_CN) and account
language to en.
  - Translate a message.
- Verify translated content displays correctly for the agent's selected
locale
  - Do the same for another locale for agent.
- With multiple translations on a message (e.g., zh_CN, es, ml), verify
the UI shows the one matching agent's locale
- Change agent locale and verify the displayed translation updates
accordingly

app/javascript/dashboard/components-next/message/MessageList.vue

@@ -42,7 +42,10 @@ const props = defineProps({
 const emit = defineEmits(['retry']);
 
 const allMessages = computed(() => {
-  return useCamelCase(props.messages, { deep: true });
+  return useCamelCase(props.messages, {
+    deep: true,
+    stopPaths: ['content_attributes.translations'],
+  });
 });
 
 const currentChat = useMapGetter('getSelectedChat');