fix(nginx): allow members settings/notifications sub-pages in buddypress

Add a location block so URLs like
/members/<user>/settings/notifications/ (and sub-pages) are passed
through to index.php instead of being redirected, matching the
handling of the other excluded BuddyPress member paths.

Author: MartinPaulEve

config/all/nginx/templates/20-buddypress.conf.template

@@ -54,3 +54,8 @@
     location ~ ^/members/[^/]+/notifications(/|$) {
         try_files $uri $uri/ /index.php?$args;
     }
+
+    # Settings: notifications and all sub-pages
+    location ~ ^/members/[^/]+/settings/notifications(/|$) {
+        try_files $uri $uri/ /index.php?$args;
+    }