Fix: show user-friendly change-password error

[smitdodiya]

Issue
The application displays technical password validation error messages to the user. (#64 )

Problem
When a user attempts to change their password without entering any value, or enters a password that is too similar to their identifier, the system displays the internal error message “The password is too similar to the user identifier”. This message is misleading, not user-friendly, and does not clearly explain what the user needs to do.

What this PR does

• Adds validation to the change password flow.
• Disables the submit button until the user enters a password in both fields.
• Improves the user experience by preventing invalid submissions and guiding users to complete all required inputs before proceeding.

[smitdodiya]

The user profile password change flow should require entering the old password first, as suggested by Rakshit.