Investigate possibly unused strings

[flodolo]

Script here: https://gist.github.com/flodolo/459a7e8e85392756e5eb72eb38613d1a

I spot checked a few, and they seem unused. I don't know if there's code outside of this repo that might be using them though.

Unreference entities:
  - app.ftl:-brand-fxa
  - app.ftl:-brand-premium
  - app.ftl:-brand-monitor-premium
  - app.ftl:-brand-github
  - app.ftl:error-hibp-throttled
  - app.ftl:error-hibp-connect
  - app.ftl:security-tips
  - app.ftl:monitor-several-emails
  - app.ftl:passwords-exposed
  - app.ftl:known-data-breaches-exposed
  - app.ftl:new-breach
  - app.ftl:error-page-error-other-title
  - app.ftl:banner-monitor-rebrand-text
  - app.ftl:banner-monitor-rebrand-dismiss-button-label
  - app.ftl:banner-monitor-rebrand-dismiss-button-tooltip
  - breaches.ftl:breach-checklist-link-firefox-relay
  - breaches.ftl:breach-checklist-link-password-manager
  - breaches.ftl:breach-checklist-link-mozilla-vpn
  - breaches.ftl:breach-checklist-pw-header-text
  - breaches.ftl:breach-checklist-pw-body-text
  - breaches.ftl:breach-checklist-email-header-2
  - breaches.ftl:breach-checklist-email-body
  - breaches.ftl:breach-checklist-ssn-header
  - breaches.ftl:breach-checklist-ssn-body-2
  - breaches.ftl:breach-checklist-cc-header
  - breaches.ftl:breach-checklist-cc-body
  - breaches.ftl:breach-checklist-bank-header
  - breaches.ftl:breach-checklist-bank-body
  - breaches.ftl:breach-checklist-pin-header
  - breaches.ftl:breach-checklist-pin-body
  - breaches.ftl:breach-checklist-ip-header-2
  - breaches.ftl:breach-checklist-ip-body
  - breaches.ftl:breach-checklist-address-header
  - breaches.ftl:breach-checklist-address-body
  - breaches.ftl:breach-checklist-dob-header
  - breaches.ftl:breach-checklist-dob-body
  - breaches.ftl:breach-checklist-phone-header-2
  - breaches.ftl:breach-checklist-sq-header-text
  - breaches.ftl:breach-checklist-sq-body-text
  - breaches.ftl:breach-checklist-hp-header
  - breaches.ftl:breach-checklist-hp-body-2
  - breaches.ftl:breach-checklist-general-header
  - dashboard.ftl:modal-exposure-status-description-all
  - email-strings.ftl:email-header-logo-alt
  - email-strings.ftl:-product-name-relay
  - email-strings.ftl:-product-name-vpn
  - email-strings.ftl:email-breach-alert-blurb
  - email-strings.ftl:email-verify-subhead
  - exposure-card.ftl:exposure-card-credit-card
  - exposure-card.ftl:exposure-card-your-exposed-info
  - fix.ftl:leaked-passwords-steps-subtitle
  - fix.ftl:leaked-security-questions-steps-subtitle
  - recommendations.ftl:rec-ssn-subhead
  - recommendations.ftl:rec-pw-3-subhead
  - recommendations.ftl:rec-pw-3-cta
  - recommendations.ftl:rec-pw-3-fx
  - recommendations.ftl:rec-pw-3-non-fx
  - recommendations.ftl:rec-pw-4-subhead
  - recommendations.ftl:rec-pw-4-cta
  - recommendations.ftl:rec-gen-1-subhead
  - recommendations.ftl:rec-gen-1-cta
  - recommendations.ftl:rec-gen-2-subhead
  - recommendations.ftl:rec-gen-2-cta
  - recommendations.ftl:rec-gen-3-subhead
  - recommendations.ftl:rec-gen-3-cta
  - recommendations.ftl:rec-gen-4-subhead
  - settings.ftl:settings-remove-email-button-tooltip
  - announcements.ftl:announcement-add-more-personal-details-title
  - announcements.ftl:announcement-add-more-personal-details-description
  - announcements.ftl:announcement-add-more-personal-details-cta-label
  - announcements.ftl:announcement-add-up-to-20-emails-plus-title
  - announcements.ftl:announcement-add-up-to-20-emails-plus-description
  - announcements.ftl:announcement-add-up-to-20-emails-plus-cta-label
  - announcements.ftl:-brand-plus
  - announcements.ftl:announcement-add-up-to-20-emails-free-title
  - announcements.ftl:announcement-add-up-to-20-emails-free-description
  - announcements.ftl:announcement-add-up-to-20-emails-free-cta-label
  - announcements.ftl:announcement-switch-to-yearly-sub-title
  - announcements.ftl:announcement-switch-to-yearly-sub-description
  - announcements.ftl:announcement-switch-to-yearly-sub-cta-label
  - dashboard-premium.ftl:dashboard-exposures-filter-exposure-removal-time-label-7
  - dashboard-premium.ftl:dashboard-exposures-filter-exposure-removal-time-label-13
  - dashboard-premium.ftl:dashboard-exposures-filter-exposure-removal-time-label-60
  - dashboard-premium.ftl:dashboard-exposures-filter-exposure-removal-time-label-90
  - dashboard-premium.ftl:dashboard-exposures-filter-exposure-removal-time-label-180
  - dashboard-premium.ftl:dashboard-exposures-filter-exposure-removal-time-label-other
  - dashboard-premium.ftl:modal-exposure-status-description-premium
  - dashboard-premium.ftl:false-door-test-content-part-one
  - dashboard-premium.ftl:false-door-test-content-part-two
  - dashboard-premium.ftl:false-door-test-content-part-two-dashboard
  - dashboard-premium.ftl:false-door-test-cta
  - dashboard-premium.ftl:false-door-test-popup-close
  - dashboard-premium.ftl:false-door-test-phase-2-content-part-one
  - dashboard-premium.ftl:false-door-test-phase-2-content-part-two
  - dashboard-premium.ftl:false-door-test-phase-2-content-part-two-dashboard
  - dashboard-premium.ftl:false-door-test-phase-3-content-part-one
  - dashboard-premium.ftl:false-door-test-phase-3-content-part-two
  - dashboard-premium.ftl:false-door-test-phase-3-content-part-two-dashboard
  - dashboard-premium.ftl:data-broker-removal-maintenance-rationale-header
  - dashboard-premium.ftl:survey-csat-answer-very-dissatisfied
  - dashboard-premium.ftl:survey-csat-answer-dissatisfied
  - dashboard-premium.ftl:survey-csat-answer-neutral
  - dashboard-premium.ftl:survey-csat-answer-satisfied
  - dashboard-premium.ftl:survey-csat-answer-very-satisfied
  - emails-all.ftl:email-monthly-free-preview
  - emails-all.ftl:email-monthly-free-intro-content
  - emails-all.ftl:email-monthly-free-cta-label
  - emails-all.ftl:email-monthly-free-fixed-heading
  - emails-all.ftl:email-monthly-free-fixed-lead
  - emails-all.ftl:email-monthly-free-fixed-section-manual-heading
  - emails-all.ftl:email-monthly-free-fixed-section-in-progress-heading
  - emails-all.ftl:email-monthly-free-fixed-section-done-heading
  - emails-all.ftl:email-monthly-free-banner-plus-heading
  - emails-all.ftl:email-monthly-free-banner-plus-content
  - emails-all.ftl:email-monthly-free-banner-plus-cta-label
  - emails-all.ftl:email-monthly-report-free-results-heading
  - emails-plus.ftl:email-plus-expiration-body-plain
  - fix-premium.ftl:fix-flow-data-broker-profiles-view-data-broker-profiles-more-dialog-trigger-label
  - fix-premium.ftl:fix-flow-data-broker-profiles-manual-remove-button-mark-fixed
  - how-it-works.ftl:how-it-works-page-data-brokers-cta-button
  - how-it-works.ftl:how-it-works-page-footersection-cta-button
  - settings-premium.ftl:settings-unsubscribe-dialog-promotion-cta-subtitle