Add latest changes from gitlab-org/gitlab@12-9-stable-ee

changelogs/unreleased/upgrade-gitlab-ui.yml

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-title: Remove special chars from previous and next items in pagination
-merge_request: 25891
-author:
-type: other

changelogs/unreleased/use-default-crossplane-stack-versions.yml

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-title: Fix installation of GitLab-managed crossplane chart
-merge_request: 27040
-author:
-type: fixed

changelogs/unreleased/use_replicate_repo_for_repo_move.yml

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-title: Use ReplicateRepository when moving repo storage
-merge_request: 26550
-author:
-type: changed

changelogs/unreleased/validate-subnets-field.yml

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-title: Validate that users selects at least two subnets in EKS Form
-merge_request: 26936
-author:
-type: fixed

changelogs/unreleased/validate_service_project_id_nil_if_template.yml

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-title: Validate absence of project_id if service is a template
-merge_request: 26563
-author:
-type: other

changelogs/unreleased/vh-snippets-content-types.yml

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-title: Remove unused Snippets#content_types method
-merge_request: 26306
-author:
-type: other

changelogs/unreleased/vh-snippets-finder-tweak.yml

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-title: Improve SnippetsFinder performance with disabled project snippets
-merge_request: 26295
-author:
-type: performance