Enable flag group_authorized_agents by default

Makes it possible to share access to a Kubernetes Agent's CI/CD tunnel
with projects other than the Kubernetes Agent's configuration project.
By default, only the Kubernetes Agent's configuration project has CI/CD
access.

Changelog: changed

config/feature_flags/development/group_authorized_agents.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/340166
 milestone: '14.3'
 type: development
 group: group::configure
-default_enabled: false
+default_enabled: true

doc/user/clusters/agent/repository.md

@@ -153,9 +153,9 @@ gitops:
 > [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/5784) in GitLab 14.3.
 
 FLAG:
-On self-managed GitLab, by default this feature is not available. To make it available,
-ask an administrator to [enable the `group_authorized_agents` flag](../../../administration/feature_flags.md).
-On GitLab.com, this feature is available.
+On self-managed GitLab, by default this feature is available. To hide the
+feature, ask an administrator to [disable the feature flag](../../../administration/feature_flags.md) named `group_authorized_agents`. On
+GitLab.com, this feature is available.
 
 If you use the same cluster across multiple projects, you can set up the CI/CD Tunnel
 to grant the Agent access to one or more groups. This way, all the projects that belong