[Bug]: Date format does not follow chosen locale in date picker

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When picking a date, e.g. when sharing a link, the format used does not follow the one in the settings. In my specific case, I have set the locale to United Kingdom (so format DD-MM-YYYY), but the date in the share panel is shown as MM-DD-YYYY. See screenshot below for reference.

Steps to reproduce

1. Set locale to United Kingdom.
2. Share a file from the Web interface.

Expected behavior

The date shown follows the selected locale.

Nextcloud Server version

29

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "nextcloud.robecchi.eu",
            "192.168.178.22"
        ],
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "29.0.5.1",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "memcache.local": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 0,
            "timeout": 0
        },
        "filelocking.enabled": true,
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "maintenance_window_start": 1,
        "theme": "",
        "loglevel": 3,
        "default_phone_region": "GB",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpsecure": "ssl",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "twofactor_enforced": "true",
        "twofactor_enforced_groups": [],
        "twofactor_enforced_excluded_groups": [
            "SOS"
        ],
        "app_install_overwrite": [
            "whiteboard"
        ]
    }
}

List of activated Apps

Enabled:
  - activity: 2.21.1
  - bruteforcesettings: 2.9.0
  - calendar: 4.7.15
  - cloud_federation_api: 1.12.0
  - comments: 1.19.0
  - contacts: 6.0.0
  - contactsinteraction: 1.10.0
  - dashboard: 7.9.0
  - dav: 1.30.1
  - federatedfilesharing: 1.19.0
  - files: 2.1.1
  - files_downloadlimit: 2.0.0
  - files_pdfviewer: 2.10.0
  - files_reminders: 1.2.0
  - files_sharing: 1.21.0
  - files_trashbin: 1.19.0
  - files_versions: 1.22.0
  - firstrunwizard: 2.18.0
  - groupfolders: 17.0.2
  - logreader: 2.14.0
  - lookup_server_connector: 1.17.0
  - nextcloud_announcements: 1.18.0
  - notes: 4.10.1
  - notifications: 2.17.0
  - oauth2: 1.17.0
  - password_policy: 1.19.0
  - photos: 2.5.0
  - provisioning_api: 1.19.0
  - qownnotesapi: 24.4.0
  - recommendations: 2.1.0
  - related_resources: 1.4.0
  - serverinfo: 1.19.0
  - settings: 1.12.0
  - sharebymail: 1.19.0
  - survey_client: 1.17.0
  - suspicious_login: 7.0.0
  - tasks: 0.16.1
  - text: 3.10.1
  - theming: 2.4.0
  - twofactor_backupcodes: 1.18.0
  - twofactor_nextcloud_notification: 3.9.0
  - twofactor_totp: 11.0.0-dev
  - updatenotification: 1.19.1
  - viewer: 2.3.0
  - workflowengine: 2.11.0
Disabled:
  - admin_audit: 1.19.0
  - calendar.bak: 2.3.3
  - circles: 29.0.0-dev (installed 23.1.1)
  - encryption: 2.17.0
  - federation: 1.19.0 (installed 1.13.0)
  - files_external: 1.21.0
  - files_rightclick: 0.15.1 (installed 1.6.0)
  - mail: 3.7.7 (installed 3.7.7)
  - metadata: 0.20.0 (installed 0.20.0)
  - privacy: 1.13.0 (installed 1.7.0)
  - support: 1.12.0 (installed 1.6.0)
  - systemtags: 1.19.0 (installed 1.13.0)
  - user_ldap: 1.20.0
  - user_status: 1.9.0 (installed 1.3.1)
  - weather_status: 1.9.0 (installed 1.3.0)
  - whiteboard: 0.0.3 (installed 0.0.3)

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

No response

Additional info

No response

Start by reproducing the date picker in the share panel through the Web interface with the locale set to United Kingdom, comparing the displayed format with the expected DD-MM-YYYY order. Identify the date-picker entry point used by that panel and verify the behavior with a locale-focused test; done means the displayed date follows the selected locale.