Fix unhandled alerts not being properly ignored (#779)

This is an improvement over #778. By falling back to the full message value from Chromedriver, we can correctly get the `:unexpected_alert` condition to match on the bizarre, not-quite-JSON message from Chromedriver like:

```
    "message" => "unexpected alert open: {Alert text : Error loading data, please refresh and try again}\n  (Session info: chrome-headless-shell=125.0.6422.142)\n  (Driver info: chromedriver=125.0.6422.78 (14db42ec38aded3304a3e624a0a038e02956b87e-refs/branch-heads/6422@{#1088}),platform=Mac OS X 14.5.0 x86_64)"
```

Applying this patch to my local copy, my default-configured Chromedriver correctly ignores the alert and my tests that passed on v0.36.6 again pass.

lib/wallaby/httpclient.ex

@@ -165,19 +165,14 @@ defmodule Wallaby.HTTPClient do
 
  defp coerce_json_message(%{"value" => %{"message" => message} = value} = response) do
  value =
- case Regex.named_captures(~r/(?<type>.*): (?<payload>{.*})\n.*/, message) do
- %{"payload" => payload, "type" => type} ->
- message =
- case Jason.decode(payload) do
- {:ok, message} -> message
- _ -> payload
- end
-
- %{
- "message" => message,
- "type" => type
- }
-
+ with %{"payload" => payload, "type" => type} <-
+ Regex.named_captures(~r/(?<type>.*): (?<payload>{.*})\n.*/, message),
+ {:ok, message} <- Jason.decode(payload) do
+ %{
+ "message" => message,
+ "type" => type
+ }
+ else
  _ ->
  value
  end