Remove duplicate security policy link from new issues page (#21441)

Signed-off-by: Robin Townsend <[email protected]>

Author: robintown

.github/ISSUE_TEMPLATE/config.yml

@@ -1,8 +1,5 @@
 blank_issues_enabled: false
 contact_links:
-  - name: Report a security vulnerability
-    url: https://github.com/vector-im/element-web/security/policy
-    about: Please review our security policy for more details
   - name: Questions & support
     url: https://matrix.to/#/#element-web:matrix.org
     about: Please ask and answer questions here.