Wait for remote version information, before deciding Robust Cache support

Currently, GATT service discovery is scheduled immediately after
connection to new LE device.

Depending on timing of Link Layer, we might not read remote version
information before checking for Robust Caching support. In this case, we
would assume device doesn't support it.

After this patch, we would wait for "remote version information" command
to finish, and go back to schedulsed service discovery. This way, we
would alawys use Robust Cache when newly connected device supports it.

Test: Bond with a set of devices, where both of them have same GATT
    database hash. Verify service discovery is triggered only once in snoop
    log.
Bug: 293249869
Change-Id: Id87ce6f8aa4a4f23a33d963dbbc28ef0891a6d75