Fix indentation in assorted docs

data/deprecations/16-9-sast-analyzer-consolidation.yml

doc/administration/license.md

doc/administration/postgresql/multiple_databases.md

doc/development/ee_features.md

...observability/gitlab_instrumentation_for_opentelemetry.md

doc/integration/google_cloud_iam.md

doc/operations/feature_flags.md

doc/subscriptions/subscription-add-ons.md

doc/topics/autodevops/multiple_clusters_auto_devops.md

doc/update/background_migrations_troubleshooting.md

doc/update/deprecations.md

doc/update/versions/gitlab_16_changes.md

doc/update/zero_downtime.md

doc/user/packages/composer_repository/index.md