✨(domains) add admin action to fetch domain DNS config

Create a Django admin action to allow retrieval of
the expected domain configuration from dimail.
These values shouldn't change unless external
intervention occurs. An admin command seems sufficient to handle
hypothetical changes.

src/backend/mailbox_manager/admin.py

@@ -101,6 +101,35 @@ def fetch_domain_status_from_dimail(modeladmin, request, queryset):  # pylint: d
         )
 
 
+@admin.action(description=_("Fetch domain expected config from dimail"))
+def fetch_domain_expected_config_from_dimail(modeladmin, request, queryset):  # pylint: disable=unused-argument
+    """Admin action to fetch domain expected config from dimail."""
+    client = DimailAPIClient()
+    excluded_domains = []
+    for domain in queryset:
+        # do not check disabled domains
+        if domain.status == enums.MailDomainStatusChoices.DISABLED:
+            excluded_domains.append(domain.name)
+            continue
+        response = client.fetch_domain_expected_config(domain)
+        if response:
+            messages.success(
+                request,
+                _(f"Domain expected config fetched with success for {domain.name}."),
+            )
+        else:
+            messages.error(
+                request, _(f"Failed to fetch domain expected config for {domain.name}.")
+            )
+    if excluded_domains:
+        messages.warning(
+            request,
+            _(
+                f"Domains disabled are excluded from fetch: {', '.join(excluded_domains)}"
+            ),
+        )
+
+
 class UserMailDomainAccessInline(admin.TabularInline):
     """Inline admin class for mail domain accesses."""
 
@@ -124,7 +153,11 @@ class MailDomainAdmin(admin.ModelAdmin):
     readonly_fields = ["created_at", "slug"]
     list_filter = ("status",)
     inlines = (UserMailDomainAccessInline,)
-    actions = (sync_mailboxes_from_dimail, fetch_domain_status_from_dimail)
+    actions = (
+        sync_mailboxes_from_dimail,
+        fetch_domain_status_from_dimail,
+        fetch_domain_expected_config_from_dimail,
+    )
 
 
 @admin.register(models.Mailbox)