[MM-32692] Add two more CRT options (#20088)

* MM-32692 Add two more CRT options deafult_on and always_on

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

model/config.go

@@ -86,6 +86,7 @@ const (
 	CollapsedThreadsDisabled   = "disabled"
 	CollapsedThreadsDefaultOn  = "default_on"
 	CollapsedThreadsDefaultOff = "default_off"
+	CollapsedThreadsAlwaysOn   = "always_on"
 
 	EmailBatchingBufferSize = 256
 	EmailBatchingInterval   = 30
@@ -3657,6 +3658,7 @@ func (s *ServiceSettings) isValid() *AppError {
 
 	if *s.CollapsedThreads != CollapsedThreadsDisabled &&
 		*s.CollapsedThreads != CollapsedThreadsDefaultOn &&
+		*s.CollapsedThreads != CollapsedThreadsAlwaysOn &&
 		*s.CollapsedThreads != CollapsedThreadsDefaultOff {
 		return NewAppError("Config.IsValid", "model.config.is_valid.collapsed_threads.app_error", nil, "", http.StatusBadRequest)
 	}

model/config_test.go

@@ -1491,6 +1491,17 @@ func TestConfigServiceSettingsIsValid(t *testing.T) {
 	err = cfg.ServiceSettings.isValid()
 	require.NotNil(t, err)
 	require.Equal(t, "model.config.is_valid.collapsed_threads.autofollow.app_error", err.Id)
+
+	*cfg.ServiceSettings.CollapsedThreads = CollapsedThreadsAlwaysOn
+	err = cfg.ServiceSettings.isValid()
+	require.NotNil(t, err)
+	require.Equal(t, "model.config.is_valid.collapsed_threads.autofollow.app_error", err.Id)
+
+	*cfg.ServiceSettings.ThreadAutoFollow = true
+	*cfg.ServiceSettings.CollapsedThreads = "test_status"
+	err = cfg.ServiceSettings.isValid()
+	require.NotNil(t, err)
+	require.Equal(t, "model.config.is_valid.collapsed_threads.app_error", err.Id)
 }
 
 func TestConfigDefaultCallsPluginState(t *testing.T) {