email: Fix regression error when installing/operation app

- In tags cleanup code, the front page shortcut for email uses different tags
than those provided in the manifest. When the app is instantiated in privileged
code without setting up Django, this causes an error even though gettext_noop is
used. Workaround by using a custom method for this.

Tests:

- Installing, enabling/disabling email apps works.

- 'make update-translations' output shows that django.pot has been updated and
the tags in question are part of the POT file.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/email/__init__.py

@@ -5,7 +5,6 @@ import logging
 
 from django.urls import reverse_lazy
 from django.utils.translation import gettext_lazy as _
-from django.utils.translation import gettext_noop
 
 import plinth.app
 from plinth import cfg, frontpage, menu
@@ -19,7 +18,7 @@ from plinth.modules.letsencrypt.components import LetsEncrypt
 from plinth.package import Packages
 from plinth.privileged import service as service_privileged
 from plinth.signals import domain_added, domain_removed
-from plinth.utils import format_lazy
+from plinth.utils import format_lazy, gettext_noop
 
 from . import aliases, manifest, privileged
 

plinth/utils.py

@@ -192,3 +192,8 @@ class SafeFormatter(string.Formatter):
             return super().get_field(field_name, args, kwargs)
         except (AttributeError, TypeError):
             return (f'?{field_name}?', '')
+
+
+def gettext_noop(message: str) -> str:
+    """Do nothing. Using this method marks the string for translation."""
+    return message