Simplify prebuilt_apex/apex_set common properties

Moves all properties common to prebuilt_apex and apex_set module types
into prebuiltCommonProperties. Removes selectedApexProperties from
Prebuilt as that duplicated, and masked, the same property in
prebuiltCommon.

Bug: 187266082
Test: m nothing
      m SOONG_CONFIG_art_module_source_build=false nothing
      - this fails but not because of missing APEX variants
Change-Id: Ice7dfb8e18bb526fdd5b41bcd518c6971564d81b