Fixed accessibility issues in Wi-Fi password view in Settings

- Keep the Save button enabled at all times

- Show "*required" or "The password is invalid" to remind the user
  - Show "Password (optional)" to indicate that it can remain unchanged, when modifying Wi-Fi configuration

Bug: 386897596
Bug: 402694144
Flag: EXEMPT bugfix
Test: Manual testing
  atest SettingsUnitTests:AddNetworkFragmentTest
  atest WifiConfigControllerTest \
        WifiConfigController2Test \
        WifiDialogActivityTest
Change-Id: I09b7684674ff376139565fcc196cde8d8d20a864

src/com/android/settings/wifi/WifiDialog2.kt

@@ -28,6 +28,7 @@ import android.widget.TextView
 import androidx.annotation.OpenForTesting
 import androidx.appcompat.app.AlertDialog
 import com.android.settings.R
+import com.android.settings.wifi.utils.WifiDialogHelper
 import com.android.settingslib.RestrictedLockUtils
 import com.android.settingslib.RestrictedLockUtilsInternal
 import com.android.wifitrackerlib.WifiEntry
@@ -68,6 +69,7 @@ open class WifiDialog2 @JvmOverloads constructor(
 
     private lateinit var view: View
     private lateinit var controller: WifiConfigController2
+    private lateinit var dialogHelper: WifiDialogHelper
 
     override fun getController(): WifiConfigController2 = controller
 
@@ -89,6 +91,7 @@ open class WifiDialog2 @JvmOverloads constructor(
         if (wifiEntry == null) {
             controller.hideForgetButton()
         }
+        dialogHelper = WifiDialogHelper(this, this, controller.validator)
     }
 
     private fun setWindowsOverlay() {