Enable SSH key lifetime settings by default

Update the documentation and toggle the ff_limit_ssh_key_lifetime
feature flag to be enabled by default.

Changelog: added
EE: true

doc/user/admin_area/settings/account_and_limit_settings.md

@@ -194,12 +194,13 @@ To set a limit on how long these sessions are valid:
 
 ## Limit the lifetime of SSH keys **(ULTIMATE SELF)**
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/1007) in GitLab 14.6 [with a flag](../../../administration/feature_flags.md) named `ff_limit_ssh_key_lifetime`. Disabled by default. 
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/1007) in GitLab 14.6 [with a flag](../../../administration/feature_flags.md) named `ff_limit_ssh_key_lifetime`. Disabled by default. 
+> - [Enabled on self-managed](https://gitlab.com/gitlab-org/gitlab/-/issues/346753) in GitLab 14.6.
 
 FLAG:
-On self-managed GitLab, by default this feature is not available. To make it available,
-ask an administrator to [enable the feature flag](../../../administration/feature_flags.md) named `ff_limit_ssh_key_lifetime`.
-On GitLab.com, this feature is not available. The feature is not ready for production use.
+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 `ff_limit_ssh_key_lifetime`.
+On GitLab.com, this feature is not available.
 
 Users can optionally specify a lifetime for
 [SSH keys](../../../ssh/index.md).

ee/app/helpers/ee/profiles_helper.rb

@@ -23,12 +23,12 @@ module EE
     end
 
     def ssh_key_expiration_policy_licensed?
-      License.feature_available?(:ssh_key_expiration_policy) && ::Feature.enabled?(:ff_limit_ssh_key_lifetime)
+      License.feature_available?(:ssh_key_expiration_policy) && ::Feature.enabled?(:ff_limit_ssh_key_lifetime, default_enabled: :yaml)
     end
 
     override :ssh_key_expiration_policy_enabled?
     def ssh_key_expiration_policy_enabled?
-      ::Gitlab::CurrentSettings.max_ssh_key_lifetime && ssh_key_expiration_policy_licensed? && ::Feature.enabled?(:ff_limit_ssh_key_lifetime)
+      ::Gitlab::CurrentSettings.max_ssh_key_lifetime && ssh_key_expiration_policy_licensed? && ::Feature.enabled?(:ff_limit_ssh_key_lifetime, default_enabled: :yaml)
     end
   end
 end

ee/config/feature_flags/development/ff_limit_ssh_key_lifetime.yml

@@ -5,4 +5,4 @@ rollout_issue_url:
 milestone: '14.6'
 type: development
 group: group::compliance
-default_enabled: false
+default_enabled: true