Reland "Replace checks for non-null parentTarget with a check for a type == Frame in the NetworkLogView."

This is a reland of commit 8be8469f1c49ac2699270555ad76a10ed4164ee4

Original change's description:
> Replace checks for non-null parentTarget with a check for a type == Frame in the NetworkLogView.
>
> Bug: 1370050
> Change-Id: I49da2fad3ea2b6bcaeff72a0d553183904bd92b3
> Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3936529
> Auto-Submit: Danil Somsikov <[email protected]>
> Reviewed-by: Wolfgang Beyer <[email protected]>
> Commit-Queue: Wolfgang Beyer <[email protected]>

Bug: 1370050
Change-Id: I55c4e5cd3822d44530eb92e40faf409bc1ea4c3e
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3944968
Commit-Queue: Danil Somsikov <[email protected]>
Reviewed-by: Wolfgang Beyer <[email protected]>
diff --git a/front_end/panels/network/NetworkLogView.ts b/front_end/panels/network/NetworkLogView.ts
index 723a8f1..d4b8cb5 100644
--- a/front_end/panels/network/NetworkLogView.ts
+++ b/front_end/panels/network/NetworkLogView.ts
@@ -831,7 +831,7 @@
 
   modelAdded(networkManager: SDK.NetworkManager.NetworkManager): void {
     // TODO(allada) Remove dependency on networkManager and instead use NetworkLog and PageLoad for needed data.
-    if (networkManager.target().parentTarget()) {
+    if (networkManager.target().parentTarget()?.type() === SDK.Target.Type.Frame) {
       return;
     }
     const resourceTreeModel = networkManager.target().model(SDK.ResourceTreeModel.ResourceTreeModel);
@@ -843,7 +843,7 @@
   }
 
   modelRemoved(networkManager: SDK.NetworkManager.NetworkManager): void {
-    if (!networkManager.target().parentTarget()) {
+    if (networkManager.target().parentTarget()?.type() !== SDK.Target.Type.Frame) {
       const resourceTreeModel = networkManager.target().model(SDK.ResourceTreeModel.ResourceTreeModel);
       if (resourceTreeModel) {
         resourceTreeModel.removeEventListener(SDK.ResourceTreeModel.Events.Load, this.loadEventFired, this);