♻️(ci) reuse amd64 to build arm64 image when possible

Building twice the image take lof of time. In soma cases, building the
arm64 image using the artifacts build in the amd64 and thant can be
reused should speed up the build of the arm64 image.

src/frontend/apps/impress/conf/default.conf

@@ -3,7 +3,7 @@ server {
   listen 3000;
   server_name localhost;
 
-  root /usr/share/nginx/html;
+  root /app;
 
   location / {
       try_files $uri index.html $uri/index.html =404;