fix(whatsapp): allow calling a contact with no existing conversation (#15014)

## Description

Agents can now place a WhatsApp call to a contact straight from the
contacts screen, even if that contact has never messaged in. Previously
the call only worked once a conversation already existed, so a freshly
added contact would fail with "Unable to start the call. Please try
again." — the only workaround was to get the contact to message the
channel first.


## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

- Manually via UI

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] 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
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] 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/components/widgets/conversation/ConversationCallButton.vue

@@ -69,9 +69,9 @@ const callButtonTooltip = computed(() =>
 const startWhatsappCall = async () => {
   if (whatsappCallSession.isInitiating.value) return;
   try {
-    const response = await whatsappCallSession.initiateOutboundCall(
-      props.chat.id
-    );
+    const response = await whatsappCallSession.initiateOutboundCall({
+      conversationId: props.chat.id,
+    });
 
     // Composable returns LOCKED when init is already in flight or a call is
     // active; soft no-op so a parallel click doesn't trigger a banner.