fix append raw error (again)

1. fixes the unintentionally added extra nesting of `{:ok, {:ok, resp}}`
  Instead, when success and raw flag set, returns `{:ok, raw_response_pb}`.
2. Adds the extra raw response check so that `append/3` returns
    `{:error, raw_unexpected_version_response_pb}` if there is the wrong
    expected version response AND raw flag set.

If I just did

```
  {:ok, response} when raw? == true ->
        {:ok, response}
```

An `{:ok, raw_unexpected_version_response_pb}` could have been returned
on unexpected version error response.

lib/spear.ex

@@ -415,12 +415,16 @@ defmodule Spear do
            messages,
            Keyword.take(opts, [:credentials, :timeout])
          ) do
-      {:ok, Streams.append_resp(result: {:success, _})} = response when raw? == true ->
+      {:ok, Streams.append_resp(result: {:success, _}) = response} when raw? == true ->
         {:ok, response}
 
       {:ok, Streams.append_resp(result: {:success, _})} ->
         :ok
 
+      {:ok, Streams.append_resp(result: {:wrong_expected_version, _}) = response}
+      when raw? == true ->
+        {:error, response}
+
       {:ok, Streams.append_resp(result: {:wrong_expected_version, expectation_violation})} ->
         {:error, Spear.Writing.map_expectation_violation(expectation_violation)}
 

test/spear_test.exs

@@ -931,17 +931,26 @@ defmodule SpearTest do
     end
 
     test "the append/3 with `raw?: true` returns the raw result", c do
-      assert {:ok, result} =
+      assert {:ok, response} =
                random_events()
                |> Stream.take(7)
                |> Spear.append(c.conn, c.stream_name, expect: :empty, raw?: true)
 
-      assert {:ok,
-              {:"event_store.client.streams.AppendResp",
-               {:success,
-                {:"event_store.client.streams.AppendResp.Success", {:current_revision, 6},
-                 {:position, {:"event_store.client.streams.AppendResp.Position", _p1, _p2}}}}}} =
-               result
+      assert {:"event_store.client.streams.AppendResp",
+              {:success,
+               {:"event_store.client.streams.AppendResp.Success", {:current_revision, 6},
+                {:position, {:"event_store.client.streams.AppendResp.Position", _p1, _p2}}}}} =
+               response
+    end
+
+    test "the append/3 with `raw?: true` returns expectation error as raw", c do
+      assert {:error, response} =
+               random_events()
+               |> Stream.take(1)
+               |> Spear.append(c.conn, c.stream_name, expect: 9999, raw?: true)
+
+      assert {:"event_store.client.streams.AppendResp",
+              {:wrong_expected_version, _wrong_expected_version_pb_tuple}} = response
     end
 
     @tag compatible(">= 21.6.0")