Add alerts for passkeys in password page

What does this MR do and why?

Add two different alerts in the password page when:

• the user has at least one passkey
• the user has no passkeys

In addition, we remove the search bar from the top of the page.

The conditions and links (to the documentation and the passkey page) are stubbed at the moment because we don't have the logic yet.

Closes #568946 (closed)

References

Screenshots or screen recordings

User without passkeys	User with passkeys

How to set up and validate locally

1. Enabled the passkeys feature flag: https://gdk.test:3443/rails/features/passkeys
2. Go to https://gdk.test:3443/-/user_settings/password
3. Currently, the two states are emulated with and without 2FA enablement.

MR acceptance checklist

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