Improve consistency of alert UX on "update password" page

Problem to solve

The following discussions from !147274 (merged) should be addressed:

• @danmh started a discussion: (+2 comments)

  issue: Not all errors display in the same way. For example here is the error when you use an invalid current password

Error 1	Error 2

Proposal

Utilize the same alert styling and placement based on guidelines in Pajamas on error messages. Use a page-level alert for errors related to form submission.