Client support for Characteristic Extended Properties

Read value of Characteristic Extended Properties descirptors as part of
GATT service discovery process. Also store this value as part of GATT
Cache.

Test: updated GattDatabaseTest.serialize_deserialize_binary_test added
 GattCacheTest.stored_attribute_to_binary_characteristic_extended_properties_test
 Added sl4a GattExtendedPropertiesTest
Bug: 110864501
Change-Id: Iccd8aa378c14e75f91d761a675c7c23f096ce2da