For #11390 - Removes redundant session observer init for ETP overlay

app/src/main/java/org/mozilla/fenix/browser/BrowserFragment.kt

@@ -147,8 +147,7 @@ class BrowserFragment : BaseBrowserFragment(), UserInteractionHandler {
         ) {
             browserToolbarView.view
         }
-        session?.register(toolbarSessionObserver, this, autoPause = true)
-        updateEngineBottomMargin()
+        session?.register(toolbarSessionObserver, viewLifecycleOwner, autoPause = true)
 
         if (settings.shouldShowFirstTimePwaFragment) {
             session?.register(
@@ -174,16 +173,6 @@ class BrowserFragment : BaseBrowserFragment(), UserInteractionHandler {
         }
     }
 
-    private fun updateEngineBottomMargin() {
-        val toolbarSessionObserver = TrackingProtectionOverlay(
-            context = requireContext(),
-            settings = requireContext().settings()
-        ) {
-            browserToolbarView.view
-        }
-        getSessionById()?.register(toolbarSessionObserver, this, autoPause = true)
-    }
-
     override fun onResume() {
         super.onResume()
         getSessionById()?.let {