🐛(admin) fix mailbox import from dimail

importing mailboxes from dimail was broken due to a change of format in dimail's
response.

src/backend/mailbox_manager/tests/test_utils_dimail_client.py

@@ -51,7 +51,7 @@ def test_dimail_synchronization__already_sync():
         rsps.add(
             rsps.GET,
             re.compile(rf".*/domains/{domain.name}/mailboxes/"),
-            body=str(
+            body=json.dumps(
                 [
                     {
                         "type": "mailbox",
@@ -129,7 +129,7 @@ def test_dimail_synchronization__synchronize_mailboxes(mock_warning):
         rsps.add(
             rsps.GET,
             re.compile(rf".*/domains/{domain.name}/mailboxes/"),
-            body=str(
+            body=json.dumps(
                 [
                     mailbox_valid,
                     mailbox_with_wrong_domain,

src/backend/mailbox_manager/utils/dimail.py

@@ -2,7 +2,6 @@
 
 """A minimalist client to synchronize with mailbox provisioning API."""
 
-import ast
 import json
 import smtplib
 from email.errors import HeaderParseError, NonASCIILocalPartDefect
@@ -346,10 +345,7 @@ class DimailAPIClient:
         if response.status_code != status.HTTP_200_OK:
             return self.raise_exception_for_unexpected_response(response)
 
-        dimail_mailboxes = ast.literal_eval(
-            response.content.decode("utf-8")
-        )  # format output str to proper list
-
+        dimail_mailboxes = response.json()
         people_mailboxes = models.Mailbox.objects.filter(domain=domain)
         imported_mailboxes = []
         for dimail_mailbox in dimail_mailboxes: