PLT-5012 Combine updateLastViewedAt, setLastViewedAt and setActiveChannel into a single API (#4840)

* Combine updateLastViewedAt, setLastViewedAt and setActiveChannel into a single API

* Remove preference DB writes

api/status_test.go

@@ -229,44 +229,3 @@ func TestGetStatusesByIds(t *testing.T) {
 		t.Fatal("should have errored")
 	}
 }
-
-/*
-func TestSetActiveChannel(t *testing.T) {
-	th := Setup().InitBasic()
-	Client := th.BasicClient
-
-	if _, err := Client.SetActiveChannel(th.BasicChannel.Id); err != nil {
-		t.Fatal(err)
-	}
-
-	status, _ := GetStatus(th.BasicUser.Id)
-	if status.ActiveChannel != th.BasicChannel.Id {
-		t.Fatal("active channel should be set")
-	}
-
-	if _, err := Client.SetActiveChannel(""); err != nil {
-		t.Fatal(err)
-	}
-
-	status, _ = GetStatus(th.BasicUser.Id)
-	if status.ActiveChannel != "" {
-		t.Fatal("active channel should be blank")
-	}
-
-	if _, err := Client.SetActiveChannel("123456789012345678901234567890"); err == nil {
-		t.Fatal("should have failed, id too long")
-	}
-
-	if _, err := Client.UpdateLastViewedAt(th.BasicChannel.Id, true); err != nil {
-		t.Fatal(err)
-	}
-
-	time.Sleep(500 * time.Millisecond)
-
-	status, _ = GetStatus(th.BasicUser.Id)
-	 need to check if offline to catch race
-	if status.Status != model.STATUS_OFFLINE && status.ActiveChannel != th.BasicChannel.Id {
-		t.Fatal("active channel should be set")
-	}
-}
-*/