MM-30338 Add feature flag for collapsedthreads (#16598)

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

api4/user_test.go

@@ -6,6 +6,7 @@ package api4
 import (
 	"fmt"
 	"net/http"
+	"os"
 	"regexp"
 	"strings"
 	"testing"
@@ -5405,6 +5406,9 @@ func TestGetThreadsForUser(t *testing.T) {
 func TestThreadSocketEvents(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
+	os.Setenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS", "true")
+	defer os.Unsetenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS")
+
 	th.App.UpdateConfig(func(cfg *model.Config) {
 		*cfg.ServiceSettings.ThreadAutoFollow = true
 		*cfg.ServiceSettings.CollapsedThreads = model.COLLAPSED_THREADS_DEFAULT_ON
@@ -5548,6 +5552,8 @@ func TestFollowThreads(t *testing.T) {
 func TestMaintainUnreadRepliesInThread(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
+	os.Setenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS", "true")
+	defer os.Unsetenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS")
 	th.App.UpdateConfig(func(cfg *model.Config) {
 		*cfg.ServiceSettings.ThreadAutoFollow = true
 		*cfg.ServiceSettings.CollapsedThreads = model.COLLAPSED_THREADS_DEFAULT_ON
@@ -5619,6 +5625,8 @@ func TestMaintainUnreadMentionsInThread(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 	Client := th.Client
+	os.Setenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS", "true")
+	defer os.Unsetenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS")
 	th.App.UpdateConfig(func(cfg *model.Config) {
 		*cfg.ServiceSettings.ThreadAutoFollow = true
 		*cfg.ServiceSettings.CollapsedThreads = model.COLLAPSED_THREADS_DEFAULT_ON