Fix puppet gem conflict when installing puppet-strings

puppet-strings 5.0.0 (released 2025-06-09) added puppet >= 8.0.0 as a
runtime dependency. The Ansible gem module defaults user_install to true,
so `gem install puppet-strings` now pulls the puppet gem into
/root/.local/share/gem/, creating a second puppet installation alongside
the puppet-agent package at /opt/puppetlabs/. When /opt/puppetlabs/bin/puppet
runs, Ruby loads both, hitting a "superclass mismatch for class Uniquefile"
fatal error that breaks all subsequent puppet commands in the playbook.

Setting user_install: false installs into the puppetlabs gem path
(/opt/puppetlabs/puppet/lib/ruby/gems/) where the bundled puppet already
satisfies the dependency, avoiding the duplicate.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

roles/foreman_installer_devel_scenario/tasks/main.yml

@@ -56,6 +56,7 @@
   gem:
     name: puppet-strings
     executable: /opt/puppetlabs/puppet/bin/gem
+    user_install: false
 
 - name: 'Install puppet/rhsm puppet module'
   command: "/opt/puppetlabs/bin/puppet module install puppet-rhsm --target-dir {{ foreman_installer_devel_scenario_modules }}"