[fenix] Closes https://github.com/mozilla-mobile/fenix/issues/855 - Remove customtab check for CustomTabToolbarFeature

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

@@ -230,8 +230,7 @@ class BrowserFragment : Fragment(), BackHandler {
         return when {
             findInPageIntegration.onBackPressed() -> true
             sessionFeature.onBackPressed() -> true
-            requireComponents.core.sessionManager.selectedSession?.isCustomTabSession()
+            customTabsToolbarFeature.onBackPressed() -> true
-                    ?: false && customTabsToolbarFeature.onBackPressed() -> true
             else -> false
         }
     }