fix(i18n): clarify ownership in password change error messages (#34092)

This PR updates the English localization messages
`password_username_disabled` and `password_full_name_disabled` to
replace "their" with "your", making it clear that the messages refer to
the currently signed-in user.

Author: hakonharnes

options/locale/locale_en-US.ini

@@ -730,8 +730,8 @@ public_profile = Public Profile
 biography_placeholder = Tell us a little bit about yourself! (You can use Markdown)
 location_placeholder = Share your approximate location with others
 profile_desc = Control how your profile is show to other users. Your primary email address will be used for notifications, password recovery and web-based Git operations.
-password_username_disabled = You are not allowed to change their username. Please contact your site administrator for more details.
-password_full_name_disabled = You are not allowed to change their full name. Please contact your site administrator for more details.
+password_username_disabled = You are not allowed to change your username. Please contact your site administrator for more details.
+password_full_name_disabled = You are not allowed to change your full name. Please contact your site administrator for more details.
 full_name = Full Name
 website = Website
 location = Location