Revert " #4755 Combining consecutive user join/leave system messages to single message and few other changes." (#7072)

* Revert "PLT-6603: Don't return all posts on invalid query. (#7061)"

This reverts commit 25a2013890.

* Revert " #4755 Combining consecutive user join/leave system messages to single message and few other changes. (#5945)"

This reverts commit 8a91235fb3.

model/post_test.go

@@ -113,48 +113,3 @@ func TestPostIsSystemMessage(t *testing.T) {
 		t.Fatalf("TestPostIsSystemMessage failed, expected post2.IsSystemMessage() to be true")
 	}
 }
-
-func TestPostIsUserActivitySystemMessage(t *testing.T) {
-	post1 := Post{Message: "test_1"}
-	post1.PreSave()
-
-	if post1.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post1.IsSystemMessage() to be false")
-	}
-
-	post2 := Post{Message: "test_2", Type: POST_JOIN_LEAVE}
-	post2.PreSave()
-	if !post2.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post2.IsSystemMessage() to be true")
-	}
-
-	post3 := Post{Message: "test_3", Type: POST_JOIN_CHANNEL}
-	post3.PreSave()
-	if !post3.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post3.IsSystemMessage() to be true")
-	}
-
-	post4 := Post{Message: "test_4", Type: POST_LEAVE_CHANNEL}
-	post4.PreSave()
-	if !post4.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post4.IsSystemMessage() to be true")
-	}
-
-	post5 := Post{Message: "test_5", Type: POST_ADD_REMOVE}
-	post5.PreSave()
-	if !post5.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post5.IsSystemMessage() to be true")
-	}
-
-	post6 := Post{Message: "test_6", Type: POST_ADD_TO_CHANNEL}
-	post6.PreSave()
-	if !post6.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post6.IsSystemMessage() to be true")
-	}
-
-	post7 := Post{Message: "test_7", Type: POST_REMOVE_FROM_CHANNEL}
-	post7.PreSave()
-	if !post7.IsUserActivitySystemMessage() {
-		t.Fatalf("TestPostIsUserActivitySystemMessage failed, expected post7.IsSystemMessage() to be true")
-	}
-}