l10n: updated Arabic (ar)
l10n: updated Arabic (ar)

contributors:
  Ahmed Essam
  Layla Taha
  andrea Sommer Ryan
  erinm

updated from:
  repo: https://github.com/freedomofpress/securedrop-i18n
  commit: 2e52ab4e092554d1244fac75be3aea51eb881717

conorsch/securedrop,conorsch/securedrop,conorsch/securedrop,conorsch/securedrop,conorsch/securedrop