title: Why Dialog does not have a NavController [Missing]?
body: <p>I am trying to use the latest update of Nav Component in my application </p>
  
  <p>where i can add dialog(<code>BottomSheetDialogFragment</code>) in my <code>nav graph</code></p>
  
  <pre><code>nav_version = "2.1.0-alpha05"
  </code></pre>
  
  <p>Part of code from my <code>nav_graph</code>:</p>
  
  <pre><code>    &lt;dialog
          android:id="@+id/settingFragment"
          android:name="com.andor.navigate.notepad.listing.fragment.SettingFragment"
          tools:layout="@layout/fragment_setting"&gt;
          &lt;action
              android:id="@+id/action_settingFragment_to_confirmationFragment"
              app:destination="@id/confirmationFragment" /&gt;
      &lt;/dialog&gt;
      &lt;dialog
          android:id="@+id/confirmationFragment"
          android:name="com.andor.navigate.notepad.ConfirmationFragment"
          tools:layout="@layout/fragment_confirmation" /&gt;
  </code></pre>
  
  <p>In my Setting's Fragment i have a button(<code>logout_btn</code>) to trigger the action: <code>action_settingFragment_to_confirmationFragment</code></p>
  
  <p>code in <code>OnActivityCreated</code> of the Setting's fragment:</p>
  
  <pre><code>    logout_btn.setOnClickListener {
         Navigation.findNavController(view!!).navigate(R.id.action_settingFragment_to_confirmationFragment)
      } 
  </code></pre>
  
  <p>When i Click on the button there is a runtime Exception:</p>
  
  <blockquote>
    <p>java.lang.IllegalStateException: View
    androidx.constraintlayout.widget.ConstraintLayout{550ae09 V.E......
    ........ 1,1-719,526} does not have a NavController set
            at androidx.navigation.Navigation.findNavController(Navigation.java:84)
            at com.andor.navigate.notepad.listing.fragment.SettingFragment$onActivityCreated$2.onClick(SettingFragment.kt:56)
            at android.view.View.performClick(View.java:7352)
            at android.view.View.performClickInternal(View.java:7318)
            at android.view.View.access$3200(View.java:846)
            at android.view.View$PerformClick.run(View.java:27800)
            at android.os.Handler.handleCallback(Handler.java:873)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:214)
            at android.app.ActivityThread.main(ActivityThread.java:7045)
            at java.lang.reflect.Method.invoke(Native Method)
            at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)</p>
  </blockquote>
  
  <p>My aim is to open a dialog from another dialog, but for some reason my dialog is not having(missing) NavController.</p>
  
  <p>I have already referred to the source <a href="https://android-review.googlesource.com/c/platform/frameworks/support/+/949238/2/navigation/integration-tests/testapp/src/main/java/androidx/navigation/testapp/LearnMoreDialogFragment.kt#23" rel="noreferrer">code</a></p>