KV watcher does not fire when key is purged

[lsxliron]

Current Behavior

watching a bucket using Gnat.Jetstream.API.KV.watch/3 does not fire an event when a key is purged

# create a bucket
bucket = "my_bucket"

# connect
{:ok, pid} = Gnat.start_link()

# create a bucket
{:ok, _info} = Gnat.Jetstream.API.KV.create_bucket(pid, bucket, history: 10)


handler = fn action, key, value ->
  IO.puts("ACTION --> #{inspect(action)}")
  IO.puts("KEY --> #{inspect(key)}")
  IO.puts("VALUE --> #{inspect(value)}")
end

# start watching the bucket
{:ok, _pid} = Gnat.Jetstream.API.KV.watch(pid, bucket, handler)

# Put the first key
:ok = Gnat.Jetstream.API.KV.create_key(pid, bucket, "my_key_1", "my_value_1")
# output:
#   ACTION --> :key_added
#   KEY --> "my_key_1"
#   VALUE --> "my_value_1"

# delete the first key
:ok = Gnat.Jetstream.API.KV.delete_key(pid, bucket, "my_key_1")
# output:
#   ACTION --> :key_deleted
#   KEY --> "my_key_1"
#   VALUE --> ""

# put the second key
:ok = Gnat.Jetstream.API.KV.put_value(pid, bucket, "my_key_2", "my_value_2")
# output:
#   ACTION --> :key_added
#   KEY --> "my_key_2"
#   VALUE --> "my_value_2"

# purge the second key
:ok = Gnat.Jetstream.API.KV.purge_key(pid, bucket, "my_key_2")
# actual output:
#   :ok
#
# expected output:
#   ACTION --> :key_deleted
#   KEY --> "my_key_2"
#   VALUE --> ""

Expected Behavior

When a key is purged the watcher should emit the same message as if the key was deleted.