Revert "Support WebView back button"

This reverts commit 9bbb411291.

app/src/main/java/org/traccar/manager/MainFragment.kt

@@ -38,9 +38,7 @@ import android.webkit.WebChromeClient
 import android.webkit.WebView
 import android.webkit.WebViewClient
 import android.webkit.WebViewFragment
-import androidx.activity.addCallback
 import androidx.appcompat.app.AlertDialog
-import androidx.appcompat.app.AppCompatActivity
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import androidx.localbroadcastmanager.content.LocalBroadcastManager
@@ -93,14 +91,6 @@ class MainFragment : WebViewFragment() {
                 .beginTransaction().replace(android.R.id.content, StartFragment())
                 .commitAllowingStateLoss()
         }
-
-        (activity as AppCompatActivity).onBackPressedDispatcher.addCallback {
-            if (webView.canGoBack()) {
-                webView.goBack();
-            } else {
-                activity.onBackPressed()
-            }
-        }
     }
 
     private val broadcastReceiver: BroadcastReceiver = object : BroadcastReceiver() {