[Tast][Fast Pair] Adds Additional data characteristic to provider impl

Adds the additional data characteristic to the chameleon provider impl.
This is a stubbed characteristic that provides no functionality, but is
required to exist in order for Fast Pair to see it as a valid provider.

BUG=b:281725799
TEST=`tast run --var=bluetooth.BTPeers=localhost:2201 localhost:2200
bluetooth.FastPairInitialPair.floss_disabled`
TEST=`run ./fast_build.sh -T`

Change-Id: I33264d0082203c593c46663c51e21e50e70833c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/chameleon/+/4608876
Reviewed-by: Shijin Abraham <shijinabraham@google.com>
Tested-by: Daniel Classon <dclasson@google.com>
Commit-Queue: Daniel Classon <dclasson@google.com>
1 file changed