[Fleet] Do not recommand user to run Fleet server in http

[nchaulet]

Description

Related to elastic/kibana#129371

We should not recommend user to run Fleet server in http and should use the default self generated certificate instead.

[mergify]

This pull request does not have a backport label. Could you fix it @nchaulet? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-/d./d is the label to automatically backport to the /d./d branch. /d is the digit
  NOTE: backport-skip has been added to this pull request.

[apmmachine]

A documentation preview will be available soon:

• 📚 HTML diff
• 📘 Fleet and Elastic Agent Guide
• 📙 Observability Guide

[dedemorton]

I think you want to remove the whole example plus the lead in sentence, "For example, the following command installs a Fleet Server and uses self-signed certs:

[nchaulet]

@dedemorton I think we want to keep that example the text is correct as it's generating self signed certificate, the option --fleet-server-insecure-http was running fleet server in http mode without generating self signed certificate this was incorrect

[dedemorton]

Ohhhhh. TBH, I have to re-learn this stuff every time I look at it. :-)

[dedemorton]

LGTM

[dedemorton]

I didn't remember having this flag in the command originally, so I looked at the history, and it looks like it was added back in January. Should we try to figure out why, or just say your revision is the correct one? b85317d Nevermind...looked through the issues and it sounds like the older UI showed it, so we wanted to show it too.