feat: add Signal to conferencing category (calcom#28724)

Co-authored-by: Sahitya Chandra <sahityajb@gmail.com>

Author: rayshivam30

packages/app-store/signal/config.json

@@ -6,7 +6,7 @@
   "logo": "icon.svg",
   "url": "https://cal.com/",
   "variant": "messaging",
-  "categories": ["messaging"],
+  "categories": ["messaging","conferencing"],
   "publisher": "Cal.com, Inc.",
   "email": "support@cal.com",
   "description": "Schedule a chat with your guests or have a Signal Video call.",