Merge branch 'netlink-fixes-for-cross-namespace-nsid-reporting'

Merge branch 'netlink-fixes-for-cross-namespace-nsid-reporting'

Ilya Maximets says:

====================
netlink: fixes for cross-namespace nsid reporting

While working on some new features for OVS and OVN we discovered that
self-referential NSIDs get unintentionally allocated in the system as
well as unexpectedly reported for local events on all-nsid listeners.

More details in the patches. They change user-visible behavior, but
the current behavior is arguably a bug, as it makes it hard to use
all-nsid sockets without a decent amount of extra unrelated work of
tracking when new NSIDs are allocated for your local namespace.

Tests are added to check the expected behavior and YNL is extended
to support all-nsid sockets in the tests.
====================

Link: https://patch.msgid.link/20260520172317.175168-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>