Update CHANGELOG.md for 9.3.0

changelogs/unreleased/31448-jira-urls.yml

...sidebar-milestone-dropdown-should-not-be-multi-select.yml

changelogs/unreleased/31483-ordered-task-list.yml

changelogs/unreleased/31510-mask-password-field-edit.yml

changelogs/unreleased/31511-jira-settings.yml

...s/unreleased/31554-update-rufus-scheduler-and-sidekiq.yml

...ether-shared-runner-is-enabled-in-the-admin-dashboard.yml

...sed/31616-add-uptime-of-gitlab-instance-in-admin-area.yml

...-inputs-when-you-try-to-add-a-tag-that-already-exists.yml

changelogs/unreleased/31633-animate-issue.yml

changelogs/unreleased/31644-make-cookie-sessions-unique.yml

...le-click-on-filter-in-search-bar-to-activate-dropdown.yml

...gs/unreleased/31781-print-rendered-files-not-possible.yml

...-controller-destroy-action-without-an-explicit-status.yml

changelogs/unreleased/31849-pipeline-real-time-header.yml

changelogs/unreleased/31849-pipeline-show-view-realtime.yml

...unreleased/31902-namespace-recent-searches-to-project.yml

changelogs/unreleased/3191-deploy-keys-update.yml

changelogs/unreleased/31943-document-go-183.yml

...quest-diff-file-size-limit-for-default-toggle-opening.yml