ci(docs-infra): fix `download_yarn` in `aio_monitoring` (#28555)

The `download_yarn` step depends on the `CI_YARN_VERSION` environment
variable and thus has to be run after the `define_env_vars` step.
Accidentally broken in [#28546][1].

[1]: https://github.com/angular/angular/pull/28546/files#diff-1d37e48f9ceff6d8030570cd36286a61R447

PR Close #28555

.circleci/config.yml

@@ -74,9 +74,7 @@ var_9: &setup_circleci_bazel_config
 var_10: &download_yarn
   run:
     name: Downloading Yarn
-    command: |
-      echo "Attempting to install $CI_YARN_VERSION from https://yarnpkg.com" |
-      curl -o- -L https://yarnpkg.com/install.sh | PROFILE=$BASH_ENV bash -s -- --version "$CI_YARN_VERSION"
+    command: curl -o- -L https://yarnpkg.com/install.sh | PROFILE=$BASH_ENV bash -s -- --version "$CI_YARN_VERSION"
 
 version: 2
 jobs:
@@ -454,8 +452,8 @@ jobs:
           <<: *post_checkout
       - restore_cache:
           key: *cache_key
-      - *download_yarn
       - *define_env_vars
+      - *download_yarn
       - run:
           name: Run tests against the deployed apps
           command: ./aio/scripts/test-production.sh $CI_AIO_MIN_PWA_SCORE

.circleci/env.sh

@@ -18,7 +18,6 @@ setPublicVar PROJECT_ROOT "$(pwd)";
 setPublicVar CI_AIO_MIN_PWA_SCORE "95";
 # This is the branch being built; e.g. `pull/12345` for PR builds.
 setPublicVar CI_BRANCH "$CIRCLE_BRANCH";
-setPublicVar CI_YARN_VERSION "1.13.0"
 # ChromeDriver version compatible with the Chrome version included in the docker image used in
 # `.circleci/config.yml`. See http://chromedriver.chromium.org/downloads for a list of versions.
 # This variable is intended to be passed as an arg to the `webdriver-manager update` command (e.g.
@@ -32,6 +31,7 @@ setPublicVar CI_COMMIT_RANGE "`[[ ${CIRCLE_PR_NUMBER:-false} != false ]] && echo
 setPublicVar CI_PULL_REQUEST "${CIRCLE_PR_NUMBER:-false}";
 setPublicVar CI_REPO_NAME "$CIRCLE_PROJECT_REPONAME";
 setPublicVar CI_REPO_OWNER "$CIRCLE_PROJECT_USERNAME";
+setPublicVar CI_YARN_VERSION "1.13.0";
 
 
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