Do not call setAlwaysButtonEnabled if the activity doesn't support defaults.

13405c55 introduced a bug where
activities using ResolverActivity without dafaults/always option get selected,
the ResolverActivity tries to set a default causing a crash.

Test: Test Application using TECH_DISCOVERED intent filter
Bug: 38358120
Change-Id: Id36635d84963bcf1dc7e55938e2370542ed291ab