fix: "Deadlinks" → "Dead links" in SECURITY.md (calcom#29292)

Closes calcom#29279

Minor typo fix in the "Out of scope vulnerabilities" list.
"Deadlinks" should be two words: "Dead links".

Co-authored-by: Premsugeendran <premsugeendran23@gmail.com>

Author: premsreelathasugeendran

SECURITY.md

@@ -23,7 +23,7 @@ better protect our clients and our systems.
 - Email spoofing
 - Missing DNSSEC, CAA, CSP headers
 - Lack of Secure or HTTP only flag on non-sensitive cookies
-- Deadlinks
+- Dead links
 
 ## Please do the following