Pixiportal

As an administrator, I want to update a user's information, so that organizational information remains accurate.

Acceptance Criteria:
-Successful update
The administrator can select an existing user and edit their information (name, email, department, team, site).
Changes are saved, and a confirmation message is shown.

-Data validation
The system checks that a modified email isn't already associated with another account.
Required fields cannot be left empty.

-Historical data preserved
Updating a user's information does not erase their historical records within the platform.

-Security
Only administrators can update user information.

"Note: US04, US05, US06 & US07 are pushed by the same ID #3748"