Feature/saajan persona (#3)

* feat: add template based email content (html + plaintext fallback)

* feat: init saajan component

* feat: add aesthetic noise background and implement Saajan component in register and login

* feat: add post seal modal for vault

* refactor: add proper props interfaces

* refactor: expose props on ui components

* feat: add ssajan in lots of flows

* fix: remove render test with no value and add aria helper for btn identification

* refactor: update email notification to account for proper arguments

* refactor:  refactor E2E auth helper and mail parsing logic

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Co-authored-by: ramvignesh-b <ramvignesh-b@github.com>

backend/letters/tests.py

@@ -396,6 +396,7 @@ class LetterTaskTest(TestCase):
                 from_email=settings.FROM_EMAIL,
                 recipient_list=[self.user.email],
                 fail_silently=False,
+                html_message=ANY,
             )
             self.assertIsNotNone(letter_to_notify1.notified_at)