[ENG-11583] Create Blank Notification Template (#11802)

* Add blank notification type and template
* Respond to CR

---------

Co-authored-by: Longze Chen <cslzchen@gmail.com>

Author: Ostap-Zherebetskyi

notifications.yaml

@@ -801,3 +801,10 @@ notification_types:
     object_content_type_model_name: abstractnode
     template: 'website/templates/empty.html.mako'
     tests: []
+
+  - name: blank
+    subject: 'PLACEHOLDER FOR EMAIL SUBJECT'
+    __docs__: ...
+    object_content_type_model_name: osfuser
+    template: 'website/templates/blank.html.mako'
+    tests: []

osf/models/notification_type.py

@@ -14,6 +14,7 @@ def get_default_frequency_choices():
 
 class NotificationTypeEnum(str, Enum):
     EMPTY = 'empty'
+    BLANK = 'blank'
     # Desk notifications
     REVIEWS_SUBMISSION_STATUS = 'reviews_submission_status'
     ADDONS_BOA_JOB_FAILURE = 'addon_boa_job_failure'

website/templates/blank.html.mako

@@ -0,0 +1,5 @@
+<%inherit file="notify_base.mako" />
+
+<%def name="content()">
+
+</%def>