Update breaking changes EA in Server mode (#1492)

Update the text to provide the solution.

We should add a link to
https://www.elastic.co/docs/reference/fleet/install-elastic-agents#elastic-agent-servers-flavor-regular

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Co-authored-by: Fabrizio Ferri-Benedetti <algernon@fastmail.com>

Author: lucabelluccini

release-notes/fleet-elastic-agent/breaking-changes.md

@@ -79,7 +79,9 @@ For more information, check [#6461]({{agent-pull}}6461) and [#2489]({{agent-pull
 ::::
 
 ::::{dropdown} Changed the default {{agent}} installation and upgrade
-The default {{agent}} installation and ugprade have been changed to include only the `agentbeat`, `endpoint-security` and `pf-host-agent` components. Additional components can be included using flags.
+The default {{agent}} installation and ugprade have been changed to include only the `agentbeat`, `endpoint-security` and `pf-host-agent` components.
+
+Additional components such as `apm` or `fleet` require passing the `--install-servers` flag or setting the `ELASTIC_AGENT_FLAVOR=servers` environment variable.
 
 For more information, check [#6542]({{agent-pull}}6542).
 ::::
@@ -110,4 +112,4 @@ For more information, check [#199226]({{kib-pull}}199226).
 In addition to the new pagination limit size of 100, retrieving agent policies without agent count is now the new default behavior, and a new query parameter `withAgentCount` was added to retrieve the agent count.
 
 For more information, check [#196887]({{kib-pull}}196887).
-::::
+::::