Use an integer for query mode

This is a no-op change. Currently, the query mode employs a
boolean value to toggle between passive and active modes. To
accommodate a broader range of query modes for different
requirements, switch to an integer value that facilitating
the addition of new modes more seamlessly.

Bug: 271067818
Test: atest FrameworksNetTests NsdManagerTest
Change-Id: Ia9a12d4581246c3a5776cd241755a10994e32454