feat: Replace express-xss-sanitizer with helmet

The security middleware `express-xss-sanitizer` has been replaced with `helmet` for enhanced security measures. `helmet` provides better protection against potential security vulnerabilities.

Signed-off-by: Mathis <yidhra@tuta.io>

package.json

@@ -12,7 +12,7 @@
     "cors": "^2.8.5",
     "express": "^4.19.2",
     "express-validator": "^7.0.1",
-    "express-xss-sanitizer": "^1.2.0",
+    "helmet": "^7.1.0",
     "jose": "^5.2.4",
     "morgan": "^1.10.0",
     "mysql2": "^3.9.7",