feat(settings): add mobile Connect this device card
Because: - We are updating pairing flows and want to land UI components / pages first. - Adds the mobile screen asking the user to confirm connecting this device. This commit: - Adds `packages/fxa-settings/src/pages/Pair2/Supplicant/ConnectThisDevice/index.tsx`. - Adds storybook stories for the page. - Adds l10n files and tests. Closes #FXA-14233