fix: install filemapper gem in generate-types cronjob

The cronjob runs in its own container without the additional-ruby-gems
init script, so filemapper must be installed directly before running
puppet generate types.

💘 Generated with Crush

Assisted-by: Claude Sonnet 4.6 via Crush <crush@charm.land>

apps/base/puppet/cronjob_generate-types.yaml

@@ -35,6 +35,7 @@ spec:
                 - -c
               args:
                 - |
+                  /opt/puppetlabs/puppet/bin/gem install filemapper toml
                   find /etc/puppetlabs/code/environments -mindepth 1 -maxdepth 1 -type d | while read -r envdir; do
                     env="$(basename "$envdir")"
                     echo "Generating types for $env"