[Media Projection] Use plain AlertDialog for 3rd party hosts instead of SystemUIDialog

This will fix a crash in Android Automotive CTS tests, where a sysui
dependency is being pulled in, and trying to create a window that
has already been created, and causing a crash.

We have done this change before (ag/25220221) for the main permission dialog, but not
for the ScreenCaptureDisabledDialog.

Test: Manual
Test: Unit tests in this CL
Fixes: 328847021
Fixes: 330661784
Flag: NONE
Change-Id: I297ef751c88909d1f351eac87c91c7bdff35ecf5