docs: [google-shopping-css] added a clarifying note to the description of the parent field in the Account resource (#13698)

- [ ] Regenerate this pull request now.

PiperOrigin-RevId: 738615787

Source-Link:
googleapis/googleapis@1bd3840

Source-Link:
googleapis/googleapis-gen@a68745c
Copy-Tag:
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Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]

packages/google-shopping-css/google/shopping/css_v1/types/accounts.py

@@ -211,6 +211,10 @@ class Account(proto.Message):
             group for CSS domains; CSS domain for MC
             accounts. Returned only if the user has access
             to the parent account.
+            Note: For MC sub-accounts, this is also the CSS
+            domain that is the parent resource of the MCA
+            account, since we are effectively flattening the
+            hierarchy.".
 
             This field is a member of `oneof`_ ``_parent``.
         label_ids (MutableSequence[int]):