use MOTD_BANNED_TAGS in motd editor view

app/__init__.py

@@ -7,7 +7,7 @@ from .routes.threads import get_post_url
 from .constants import (
     PermissionLevel, permission_level_string,
     InfoboxKind, InfoboxHTMLClass,
-    REACTION_EMOJI,
+    REACTION_EMOJI, MOTD_BANNED_TAGS,
     )
 from .lib.babycode import babycode_to_html, EMOJI, BABYCODE_VERSION
 from datetime import datetime
@@ -176,6 +176,7 @@ def create_app():
             "__commit": commit,
             "__emoji": EMOJI,
             "REACTION_EMOJI": REACTION_EMOJI,
+            "MOTD_BANNED_TAGS": MOTD_BANNED_TAGS,
         }
 
     @app.context_processor