fix(config): correct slack image url in talisman (#32778)

docs/docs/security/security.mdx

@@ -280,6 +280,49 @@ TALISMAN_CONFIG = {
     "content_security_policy": { ...
 ```
 
+#### Configuring Talisman in Superset
+
+Talisman settings in Superset can be modified using superset_config.py. If you need to adjust security policies, you can override the default configuration.
+
+Example: Overriding Talisman Configuration in superset_config.py for loading images form s3 or other external sources.
+
+```python
+TALISMAN_CONFIG = {
+    "content_security_policy": {
+        "base-uri": ["'self'"],
+        "default-src": ["'self'"],
+        "img-src": [
+            "'self'",
+            "blob:",
+            "data:",
+            "https://apachesuperset.gateway.scarf.sh",
+            "https://static.scarf.sh/",
+            # "https://cdn.brandfolder.io", # Uncomment when SLACK_ENABLE_AVATARS is True  # noqa: E501
+            "ows.terrestris.de",
+            "aws.s3.com", # Add Your Bucket or external data source
+        ],
+        "worker-src": ["'self'", "blob:"],
+        "connect-src": [
+            "'self'",
+            "https://api.mapbox.com",
+            "https://events.mapbox.com",
+        ],
+        "object-src": "'none'",
+        "style-src": [
+            "'self'",
+            "'unsafe-inline'",
+        ],
+        "script-src": ["'self'", "'strict-dynamic'"],
+    },
+    "content_security_policy_nonce_in": ["script-src"],
+    "force_https": False,
+    "session_cookie_secure": False,
+}
+```
+
+# For more information on setting up Talisman, please refer to
+https://superset.apache.org/docs/configuration/networking-settings/#changing-flask-talisman-csp
+
 ### Reporting Security Vulnerabilities
 
 Apache Software Foundation takes a rigorous standpoint in annihilating the security issues in its