In password-update sign-in flow, block user if password and its confirmation do not match

[jonboiser]

Summary

Fixes #7810

Here's a gif of the password validation at work, which is similar to the user creation workflow:

Reviewer guidance

This needs to be set up as described in #7810. Basically

1. When facility settings do not require passwords, create a learner as an admin
2. Change facility settings to require passwords
3. Try to login as the learner from step 1

Contributor Checklist

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Testing:

• Contributor has fully tested the PR manually
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Reviewer Checklist

• Automated test coverage is satisfactory
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• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
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[jonboiser]

@metodimilevqa This should fix #7810

[metodimilevqa]

I confirm the fix of #7810 is successful.