[fenix] For https://github.com/mozilla-mobile/fenix/issues/1966: Up button should cancel multi-selection first (https://github.com/mozilla-mobile/fenix/pull/3108)

app/src/main/java/org/mozilla/fenix/HomeActivity.kt

@@ -71,6 +71,9 @@ open class HomeActivity : AppCompatActivity() {
         val navigationToolbar = findViewById<Toolbar>(R.id.navigationToolbar)
         setSupportActionBar(navigationToolbar)
         NavigationUI.setupWithNavController(navigationToolbar, navHost.navController, appBarConfiguration)
+        navigationToolbar.setNavigationOnClickListener {
+            onBackPressed()
+        }
         supportActionBar?.hide()
 
         intent

app/src/main/res/layout/toolbar_selected_bookmarks.xml

@@ -1,11 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    android:id="@+id/selectionToolbar"
-    android:layout_width="match_parent"
-    android:layout_height="56dp"
-    app:titleMarginStart="16dp"
-    app:titleMarginEnd="16dp"
-    app:titleTextAppearance="@style/ToolbarTitleTextStyle"
-    android:background="?foundation"
-    android:elevation="8dp"/>