Revert "MM-14845: Fix Update and Patch channel for private channels. (#10539)" (#10599)

This reverts commit 0bef611f7a.

api4/channel_test.go

@@ -212,10 +212,6 @@ func TestUpdateChannel(t *testing.T) {
 		t.Fatal("Update failed for Purpose in private channel")
 	}
 
-	// Updating a private channel requires permission *and* membership, so this should fail.
-	_, resp = th.SystemAdminClient.UpdateChannel(private)
-	CheckForbiddenStatus(t, resp)
-
 	//Non existing channel
 	channel1 := &model.Channel{DisplayName: "Test API Name for apiv4", Name: GenerateTestChannelName(), Type: model.CHANNEL_OPEN, TeamId: team.Id}
 	_, resp = Client.UpdateChannel(channel1)
@@ -325,15 +321,8 @@ func TestPatchChannel(t *testing.T) {
 	_, resp = th.SystemAdminClient.PatchChannel(th.BasicChannel.Id, patch)
 	CheckNoError(t, resp)
 
-	Client.Logout()
-	Client.Login(th.BasicUser.Username, th.BasicUser.Password)
-
-	_, resp = th.Client.PatchChannel(th.BasicPrivateChannel.Id, patch)
-	CheckNoError(t, resp)
-
-	// Patching a private channel requires permission *and* membership, so this should fail.
 	_, resp = th.SystemAdminClient.PatchChannel(th.BasicPrivateChannel.Id, patch)
-	CheckForbiddenStatus(t, resp)
+	CheckNoError(t, resp)
 
 	// Test updating the header of someone else's GM channel.
 	user1 := th.CreateUser()