Function whatsapp_empty_group_list_is_newly_closed 

pub fn whatsapp_empty_group_list_is_newly_closed(
    _mode: &WhatsAppWebMode,
    group_policy: &WhatsAppChatPolicy,
) -> bool

Whether an empty allowed_groups is a capability the operator is LOSING.

The change this reports is narrow: the empty group-identity gate moves from admit-all to policy-selected. Only a configuration that previously reached the chat-type gate and was admitted there loses anything.

Two policies lose nothing and are therefore never reported:

• all admits every group before and after.
• ignore rejects every group before and after. It is mode-independent in the chat-type gate, so a Business channel with ignore was already closed just as a Personal one was. Reporting it would tell an operator their channel used to answer every group and offer ways to reopen a policy they set deliberately.

mode is accepted so callers need not know that the answer is currently mode-independent, and so a future policy that IS mode-sensitive has a place to land without changing every call site.

Shared rather than duplicated: the Web transport emits a startup notice from this same predicate, so the runtime behavior and the config validate warning cannot drift into disagreeing about which configurations changed.