[monorepo] avoid corepack network requests (#33502)

* [monorepo] avoid corepack network requests

- Download yarn via corepack as the first step in all the docker files
- Turn off networking in corepack
- Do not run things in the upstream node image
  Instead, use the monorepo image, or base layer in all the services.
- Always build the base layer when running tests (uses cache)

* [monorepo] install corepack in shared place

* [clsi-lb] remove unrelated changes

* [web] add missing DC_RUN_FLAGS

* [monorepo] only rebuild test images locally

Also remove spurious build config in docker-compose.ci.yml.

* [server-ce] test: make yarn files available to host-admin and e2e

* [monorepo] put the corepack install snippet in a few more places

GitOrigin-RevId: 38005016ae5a708e12295e246269d6c18fece937

dockerfiles/cypress/Dockerfile

@@ -2,10 +2,15 @@ FROM cypress/included:15.12.0
 ARG USER_UID=1000
 ARG USER_GID=1000
 
+# Corepack setup, shared between all the images.
+ENV PATH="/overleaf/node_modules/.bin:$PATH"
+ENV COREPACK_HOME=/opt/corepack
+RUN corepack enable && corepack install -g yarn@4.14.1
+ENV COREPACK_ENABLE_NETWORK=0
+
 WORKDIR /overleaf
 
-RUN corepack enable \
-&&  sed -i s/node:x:1000:/node:x:${USER_GID}:/ /etc/group \
+RUN sed -i s/node:x:1000:/node:x:${USER_GID}:/ /etc/group \
 &&  sed -i s_node:x:1000:1000::/home/node:/bin/bash_node:x:${USER_UID}:${USER_GID}::/home/node:/bin/bash_ /etc/passwd \
 &&  chown -R node:node /home/node \
 &&  chown node:node /overleaf