Disable "internal" when adoption not possible.

When adoption isn't possible, we shortcut to try formatting as
external, but that still results in a warning dialog that the user
could cancel away from and then manually pick "internal."

Bug: 110863258
Test: atest com.android.settings.ui.StorageWizardTest
Change-Id: I04645c3fce11a883c10996772d73440a0dcd51ec

src/com/android/settings/deviceinfo/StorageWizardInit.java

@@ -56,6 +56,7 @@ public class StorageWizardInit extends StorageWizardBase {
 
         if (!mDisk.isAdoptable()) {
             // If not adoptable, we only have one choice
+            mInternal.setEnabled(false);
             onNavigateExternal(null);
         } else if (!mIsPermittedToAdopt) {
             // TODO: Show a message about why this is disabled for guest and