[MM-16798] Add a Guest Accounts feature flag (#13231)

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

model/license.go

@@ -59,6 +59,7 @@ type Features struct {
 	MessageExport             *bool `json:"message_export"`
 	CustomPermissionsSchemes  *bool `json:"custom_permissions_schemes"`
 	CustomTermsOfService      *bool `json:"custom_terms_of_service"`
+	GuestAccounts             *bool `json:"guest_accounts"`
 	GuestAccountsPermissions  *bool `json:"guest_accounts_permissions"`
 	IDLoadedPushNotifications *bool `json:"id_loaded"`
 	LockTeammateNameDisplay   *bool `json:"lock_teammate_name_display"`
@@ -84,6 +85,7 @@ func (f *Features) ToMap() map[string]interface{} {
 		"data_retention":              *f.DataRetention,
 		"message_export":              *f.MessageExport,
 		"custom_permissions_schemes":  *f.CustomPermissionsSchemes,
+		"guest_accounts":              *f.GuestAccounts,
 		"guest_accounts_permissions":  *f.GuestAccountsPermissions,
 		"id_loaded":                   *f.IDLoadedPushNotifications,
 		"lock_teammate_name_display":  *f.LockTeammateNameDisplay,
@@ -168,6 +170,10 @@ func (f *Features) SetDefaults() {
 		f.CustomPermissionsSchemes = NewBool(*f.FutureFeatures)
 	}
 
+	if f.GuestAccounts == nil {
+		f.GuestAccounts = NewBool(*f.FutureFeatures)
+	}
+
 	if f.GuestAccountsPermissions == nil {
 		f.GuestAccountsPermissions = NewBool(*f.FutureFeatures)
 	}