Fix nginx syntax

This file gets included in an http block for which I didn't encount, so
we can't nest it in another one.

ci/Dockerfile.assets.server

@@ -156,15 +156,13 @@ COPY --from=base /tmp/final "/usr/share/nginx/html"
 
 # Replace default nginx config
 RUN rm -rf /etc/nginx/conf.d/default.conf && echo -e $'\
-  http {\n \
   gzip on;\n \
   gzip_static on;\n \
   gzip_vary on;\n \
   gzip_comp_level 5;\n \
   gzip_min_length 256;\n \
   gzip_proxied expired no-cache no-store private auth;\n \
   gzip_types application/atom+xml application/geo+json application/javascript application/json application/ld+json application/manifest+json applicatio  n/rdf+xml application/vnd.ms-fontobject application/wasm application/x-rss+xml application/x-web-app-manifest+json application/xhtml+xml application/xliff+xm  l application/xml font/collection font/otf font/ttf image/bmp image/svg+xml image/vnd.microsoft.icon text/cache-manifest text/calendar text/css text/csv text/javascript text/markdown text/plain text/vcard text/vnd.rim.location.xloc text/vtt text/x-component text/xml;\n \
-  }\n \
   server {\n \
   \troot  /usr/share/nginx/html;\n \
   \tadd_header Access-Control-Allow-Origin *;\n \