Update IntentFlags to include MATCH_EXTERNAL

MATCH_EXTERNAL was introduced in api level 28, which was after the
initial version of this application.

This caused a bug for suggestions which assumed the enumeration was
total. This also includes a defensive check + log warning for unkown
flags.

Test: Build and Run
Change-Id: I153985b5fd576baf80545b4737648745b421f11e