Login Page does not show "Global" banner (set in kbn server args)

[wayneseymour]

Kibana version:
latest main

Elasticsearch version:
latest main

Server OS version:
Mac OS X

Browser version:
Latest MSFT Edge

Browser OS version:

Original install method (e.g. download page, yum, from source, etc.):
from source
Describe the bug:
Login Page does not show global banner

Steps to reproduce:

1. Set global banner via server args:

    kbnTestServer: {
      ...kibanaFunctionalConfig.get('kbnTestServer'),
      serverArgs: [
        ...kibanaFunctionalConfig.get('kbnTestServer.serverArgs'),
        '--xpack.banners.placement=top',
        '--xpack.banners.textContent="global banner text"',
      ],
    },

2. Login

Expected behavior:
Seeing the "global" banner
Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:
Affects: #135783

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[pgayvallet]

Reproduced using kibana.yml configuration.

After some investigation, it was caused by #129555 that stopped loading all plugins on anonymous pages.

Adding "enabledOnAnonymousPages": true, to the banners's plugin manifest addresses the issue:

cc @elastic/kibana-security before I push a PR, could you just confirm that we're fine adding the banners plugin to the list of plugins loaded on anonymous pages (just wants to make sure we're not breaking the purpose of #129555 by doing so)

[azasypkin]

cc https://github.com/orgs/elastic/teams/kibana-security before I push a PR, could you just confirm that we're fine adding the banners plugin to the list of plugins loaded on anonymous pages (just wants to make sure we're not breaking the purpose of #129555 by doing so)

It looks like there is only one potentially sensitive part in the banners plugin - xpack.banners.textContent config and it's not exposed to the browser. Considering that, I don't see any issues with loading banners in "anonymous" context if we need to.