Update CHANGELOG.md for 12.3.0

[ci skip]

changelogs/unreleased/54331-pipeline-graph-extend-scroll-area.yml

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-title: Extend pipeline graph scroll area to full width
-merge_request: 14870
-author:
-type: changed

changelogs/unreleased/55095-show-cluster-on-job.yml

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-title: Show link to cluster used on job page
-merge_request: 32446
-author:
-type: added

changelogs/unreleased/55360-redundant-index-in-the-releases-table_v2.yml

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-title: Removed redundant index on releases table
-merge_request: 31487
-author:
-type: removed

changelogs/unreleased/55999-misleading-pipeline-tooltip-messages-and-misleading-ci-status-icons.yml

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-title: Remove "Commit" from pipeline status tooltips
-merge_request: 31861
-author:
-type: fixed

changelogs/unreleased/56130-deployed_at.yml

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-title: Replace finished_at with deployed_at for the internal API Deployment entity
-merge_request: 32000
-author:
-type: other

changelogs/unreleased/56130-operations-environments-shows-incorrect-deployment-date-for-manual-.yml

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-title: Update the timestamp in Operations > Environments to show correct deployment
-  date for manual deploy jobs
-merge_request: 32072
-author:
-type: fixed

changelogs/unreleased/56295-some-avatars-not-visible-in-commit-trailers.yml

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-title: Fix for missing avatar images dislpayed in commit trailers.
-merge_request: 32374
-author: Jesse Hall @jessehall3
-type: fixed

changelogs/unreleased/57402-upate-issues-list-sort-options.yml

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-title: Updates issues REST API to allow extended sort options
-merge_request: 31849
-author:
-type: changed

changelogs/unreleased/57538-not-null-constraint-on-users-private-profile.yml

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-title: Setting NOT NULL constraint to users.private_profile column
-merge_request: 14838
-author:
-type: other

changelogs/unreleased/57657-promote-label-to-group-label-via-api-endpoint.yml

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-title: 'API: Promote project labels to group labels'
-merge_request: 25218
-author: Robert Schilling
-type: added

changelogs/unreleased/57783-better-indication-that-an-issue-has-been-duplicated.yml

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-title: Indicate on Issue Status if an Issue was Duplicated
-merge_request: 32472
-author:
-type: changed

changelogs/unreleased/59053-no-oauth-for-cicd-github-fe.yml

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-title: Remove oauth form from GitHub CI/CD only import authentication
-merge_request: 31488
-author:
-type: changed

changelogs/unreleased/59729-estimate-quick-action-does-not-produce-correct-time-for-1mo.yml

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-title: Fix parsing of months in time tracking commands
-merge_request: 32165
-author:
-type: fixed

changelogs/unreleased/59786-show-renamed-file-in-mr.yml

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-title: Fix to show renamed file in mr
-merge_request: 31888
-author:
-type: changed

changelogs/unreleased/60141-mr-resolve-conflicts-file-headers-bad-positioning-on-scroll.yml

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-title: Fix file header style and position during scroll in a merge conflict resolution
-merge_request: 31991
-author:
-type: fixed

changelogs/unreleased/60372-milestone-link-prevent-delete-issue-after-move-it-to-another-projec.yml

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-title: Add service to transfer Group Milestones when transferring a Project
-merge_request: 31778
-author:
-type: added

changelogs/unreleased/60561-quick-action-label-first-for-issue.yml

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-title: Quick action label must be first in issue comment
-merge_request: 32367
-author: Romain Maneschi
-type: fixed

changelogs/unreleased/60724-watch-button.yml

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-title: Fix watch button styling and notifications buttons consistency
-merge_request: 32827
-author:
-type: fixed

changelogs/unreleased/61385-replace-vue-resource.yml

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-title: Replaced vue resource to axios in the  Markdown field preview component
-merge_request: 32386
-author: Prakash Chokalingam @prakash_Chokalingam
-type: fixed

changelogs/unreleased/61841-fix-encoding-error-in-mr-diffs.yml

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-title: Fix encoding error in MR diffs when using external diffs
-merge_request: 32862
-author: Hiroyuki Sato
-type: fixed