ChooserSelector shouldn't crash w/o IntentResolver

If we don't have the new (so-called "unbundled") IntentResolver
package installed on a device, we'll just fall back to the system
Chooser -- we shouldn't crash trying to control an experiment that
wouldn't have any effect on that device in the first place.

Test: Build (will also check fixed regressions before merge)
Bug: 253190011
Change-Id: I2a6b49c6fb39a730759c182f8b8245b1ccc813c9