👔(dimail) allow creation of "pending" mailboxes

Previously, mailbox creation was restricted to "enabled" domains.
We now allow users to create mailboxes on pending and failed domains.
Mailboxes thus created have the "pending" mailboxes status.

src/backend/mailbox_manager/models.py

@@ -10,7 +10,11 @@ from django.utils.translation import gettext_lazy as _
 
 from core.models import BaseModel
 
-from mailbox_manager.enums import MailDomainRoleChoices, MailDomainStatusChoices
+from mailbox_manager.enums import (
+    MailboxStatusChoices,
+    MailDomainRoleChoices,
+    MailDomainStatusChoices,
+)
 
 
 class MailDomain(BaseModel):
@@ -184,6 +188,11 @@ class Mailbox(BaseModel):
     secondary_email = models.EmailField(
         _("secondary email address"), null=False, blank=False
     )
+    status = models.CharField(
+        max_length=20,
+        choices=MailboxStatusChoices.choices,
+        default=MailboxStatusChoices.PENDING,
+    )
 
     class Meta:
         db_table = "people_mail_box"
@@ -196,14 +205,8 @@ class Mailbox(BaseModel):
 
     def clean(self):
         """
-        Mailboxes can only be created on enabled domains.
-        Also, mail-provisioning API credentials must be set for dimail to allow auth.
+        Mail-provisioning API credentials must be set for dimail to allow auth.
         """
-        if self.domain.status != MailDomainStatusChoices.ENABLED:
-            raise exceptions.ValidationError(
-                "You can create mailbox only for a domain enabled"
-            )
-
         # Won't be able to query user token if MAIL_PROVISIONING_API_CREDENTIALS are not set
         if not settings.MAIL_PROVISIONING_API_CREDENTIALS:
             raise exceptions.ValidationError(
@@ -216,6 +219,11 @@ class Mailbox(BaseModel):
         """
         self.full_clean()
 
+        if self.domain.status == MailDomainStatusChoices.DISABLED:
+            raise exceptions.ValidationError(
+                _("You can't create a mailbox for a disabled domain.")
+            )
+
         if self._state.adding:
             return super().save(*args, **kwargs)