Remove ajv as an explicit dependency

There was an issue that `ajv` is not installed by mistake.
This issue have been fixed on upstream, a few years ago.

Now, we can revert the change.
This commit partially reverts 985d57a
See sameersbn/gitlab#1358

It seems that fix MR on upstream is https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/14543
but we cannot check diff because source / target branch removed by mistake

Anyway, no need to add ajv as an explicit dependency with (at least) gitlab v11 or later

Author: kkimurak

assets/build/install.sh

@@ -203,7 +203,6 @@ chown ${GITLAB_USER}: ${GITLAB_INSTALL_DIR}/config/database.yml
 
 # Installs nodejs packages required to compile webpack
 exec_as_git yarn install --production --pure-lockfile
-exec_as_git yarn add ajv@^4.0.0
 
 echo "Compiling assets. Please be patient, this could take a while..."
 exec_as_git bundle exec rake gitlab:assets:compile USE_DB=false SKIP_STORAGE_VALIDATION=true NODE_OPTIONS="--max-old-space-size=4096"

assets/runtime/functions

@@ -2168,7 +2168,6 @@ migrate_database() {
       echo "Prepare recomplie assets... Installing missing node_modules for assets"
       chown -R ${GITLAB_USER}: ${GITLAB_HOME}/gitlab/node_modules
       exec_as_git yarn install --production --pure-lockfile
-      exec_as_git yarn add ajv@^4.0.0
       echo "Recompiling assets (relative_url in use), this could take a while..."
       exec_as_git bundle exec rake gitlab:assets:compile NODE_OPTIONS="--max-old-space-size=4096" >/dev/null 2>&1
     fi