Shared channels auto-share DM & group messages (#26097)

* option for auto inviting plugin to all shared channels.
* auto-invite remotes to shared channels when flag set

server/channels/app/reaction_test.go

@@ -98,9 +98,9 @@ func TestSaveReactionForPost(t *testing.T) {
 
 func TestSharedChannelSyncForReactionActions(t *testing.T) {
 	t.Run("adding a reaction in a shared channel performs a content sync when sync service is running on that node", func(t *testing.T) {
-		th := Setup(t).InitBasic()
+		th := setupSharedChannels(t).InitBasic()
 
-		sharedChannelService := NewMockSharedChannelService(nil)
+		sharedChannelService := NewMockSharedChannelService(th.Server.GetSharedChannelSyncService())
 		th.Server.SetSharedChannelSyncService(sharedChannelService)
 		testCluster := &testlib.FakeClusterInterface{}
 		th.Server.Platform().SetCluster(testCluster)
@@ -133,9 +133,9 @@ func TestSharedChannelSyncForReactionActions(t *testing.T) {
 	})
 
 	t.Run("removing a reaction in a shared channel performs a content sync when sync service is running on that node", func(t *testing.T) {
-		th := Setup(t).InitBasic()
+		th := setupSharedChannels(t).InitBasic()
 
-		sharedChannelService := NewMockSharedChannelService(nil)
+		sharedChannelService := NewMockSharedChannelService(th.Server.GetSharedChannelSyncService())
 		th.Server.SetSharedChannelSyncService(sharedChannelService)
 		testCluster := &testlib.FakeClusterInterface{}
 		th.Server.Platform().SetCluster(testCluster)