fix(encryption): bind personal private key password inputs

[joshtrichards]

• Resolves: [Bug]: Errors when changing login password in a server with SSE user encryption #61955

Summary

Bind the password inputs in SettingsPersonalChangePrivateKey.vue to the refs used by onSubmit().

Changes

• add v-model binding for the old log-in password field
• add v-model binding for the current log-in password field
• mark both fields as required

TODO

• Backport to whenever Vue implemented was changed (TBD but at least v34; possibly v33 too)
• A follow-up PR should get implemented with frontend testing for SSE

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[joshtrichards]

/compile

[joshtrichards]

/backport to stable34

[joshtrichards]

/backport to stable33