Revert "nginx: disable gzip for SSE endpoints"

This reverts commit 51d1efead6.

This doesn't work. What we want is something like:

map $sent_http_content_type $buffering {
    default                     "on";         # Enable buffering by default
    "text/event-stream"         "off";         # Disable buffering for SSE responses
}

proxy_buffering $buffering;

unfortunately, proxy_buffering does not support variables.
https://mailman.nginx.org/pipermail/nginx/2023-November/ZGQLNBVQEG5KNLH55HTR4R4NFODBSIU3.html

Upstream has to possibly to X-Accel-Buffering to 'no' . Otherwise, we have to ship
nginx in the package.

src/nginxconfig.ejs

@@ -131,11 +131,8 @@ server {
     gzip_min_length 18k;
     gzip_types text/css text/javascript text/xml text/plain application/javascript application/x-javascript application/json;
 
-    # compression chunking logic will interfere with SSE packet flushing
-    gzip_disable "text/event-stream";
-
-    # what responses are proxied
-    gzip_proxied no-cache no-store private expired auth;
+    # enable for proxied requests as well
+    gzip_proxied any;
 
 <% if ( endpoint === 'dashboard' || endpoint === 'ip' || endpoint === 'setup' ) { -%>
     # CSP headers for the dashboard resources