[Fleet] Hide Fleet Server policies in standalone agent instructions

[jen-huang]

From discussion in this PR: #97681 (comment)

We now show Fleet Server-specific instructions for the user when they select an agent policy that contains Fleet Server. These instructions are shown in Enroll in Fleet tab aka managed mode with the assumption that the user will want to see their Fleet Server agent in Kibana.

But what about for Run standalone tab where we show instructions for enrolling standalone agents? Is there ever a use case for a "standalone Fleet Server"? Probably not, so we should consider hiding Fleet Server agent policies from the selection dropdown on that tab.

cc @mostlyjason

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[ruflin]

Fleet-Server is only used in the managed mode. It should not show up in standalone.

[Zacqary]

Is this a simple check to hide policies with is_default_fleet_server: true or do we need to poll the package policies to see if they have the Fleet Server integration added?

[jen-huang]

@Zacqary In my mind all policies that contain fleet_server package should be excluded. The reason is because the instructions for standing up an agent with Fleet Server is different than normal agents and there is no concept of a "stand alone Fleet Server agent".

[Zacqary]

@jen-huang The way the UI works right now is that it fetches the integration packages after the user selects the policy from the dropdown. With that in mind, I wonder if it would make sense to:

• Hide is_default_fleet_server policies
• Show all other policies, but display any fleet_server package badges in red and display a warning indicating that fleet_server won't work in standalone mode (but other packages will)

[jen-huang]

@Zacqary 👍🏻 That proposal sounds good to me!