Fix date format and password label in Cosmic Greeter (minor bug)

[roxfr]

Virtualbox 7.1.0 ; Pop!_OS 24.04 LTS x86_64 (amd64 nvidia 9)

Hi,

The current implementation of the Cosmic Greeter does not fully support the French language. Specifically, the date is not displayed in French, and the term 'password:' is not translated, which should appear as 'mot de passe :'.

Steps to reproduce:

• Set the system language to French.
• Launch the Cosmic Greeter.
• Observe that the date is displayed in English.
• Observe that the label for the password field is 'password:' instead of 'mot de passe :'.

Expected behavior:

• The date should be displayed in French.
• The label for the password field should be translated to 'mot de passe :'.

Please correct this minor bug to enhance the user experience. Thank you. Best regards, Roxfr