refactor(settings): Upgrade to React 19

[xlisachan]

Because

• Commit 1
  • react-hook-form v6 does not support React 19, blocking the planned upgrade
  • v6 is unmaintained and has known issues with formState reactivity

This pull request

• Commit 1
  • Bumps react-hook-form from ^6.15.8 to ^7.54.0
  • Adds registration prop to InputText/InputPassword for v7's register() API
  • Migrates all 30+ form components from inputRef={register({...})} to registration={register('fieldName', {...})}
  • Updates type interfaces from UseFormMethods to UseFormReturn
  • Moves errors from top-level useForm destructure to formState.errors
  • Fixes InputPhoneNumber to use setValue with shouldDirty/shouldValidate (v7 no longer auto-tracks dirty state via setValue)
  • Updates tests for v7's async formState updates (userEvent over fireEvent, waitFor for formState assertions, VerifiedSessionGuard mock)
• Commit 2
  • Upgrade React 18 to 19, react-hook-form v6 to v7
• Commit 3
  • Extract lazy() from test-utils to avoid prod dependency on test helpers

Issue that this pull request solves

Closes: PAY-3633

Checklist

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• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.