element-web: Use a wider CSP default

X-Frame-Options should be the source of truth for this particular policy
decision, but it seems some browsers aren't collating the two correctly,
so a slightly wider CSP policy allows those to behave reasonably.

charts/element-web/Chart.yaml

@@ -10,7 +10,7 @@ icon: https://element.io/images/logo-mark-primary.svg
 appVersion: 1.11.42
 
 type: application
-version: 1.2.13
+version: 1.3.0
 
 maintainers:
   - name: Alexander Olofsson

charts/element-web/values.yaml

@@ -34,7 +34,7 @@ nginxConfig: |-
   add_header X-Frame-Options SAMEORIGIN;
   add_header X-Content-Type-Options nosniff;
   add_header X-XSS-Protection "1; mode=block";
-  add_header Content-Security-Policy "frame-ancestors 'none'";
+  add_header Content-Security-Policy "frame-ancestors 'self'";
 
 ## Configuration for mounting additional volumes into the application container.
 ##