fix(jsonrpc): enable HTTP basic auth in WS client (#2434)

Hello,

I noticed that the JSON-RPC client is compatible with URLs containing
**HTTP basic auth**, but not on the WebSocket side.

For instance:

```golang
client, err := http.New("https://foo:bar@example.org:443", "/websocket")

client.Block(ctx, nil) // works

client.Start() // websocket error: the client doesn't forward auth headers
```

The HTTP client handle the username/password from the given endpoint
correctly:
-
https://github.com/cometbft/cometbft/blob/v0.38.5/rpc/jsonrpc/client/http_json_client.go#L140-L141
-
https://github.com/cometbft/cometbft/blob/v0.38.5/rpc/jsonrpc/client/http_json_client.go#L184-L185


So this PR brings the same logic for the WS client.

---

#### PR checklist

- [ ] Tests written/updated
- [x] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [ ] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [x] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec

.changelog/unreleased/improvements/2434-jsonrpc-websocket-basic-auth.md

@@ -0,0 +1 @@
+- `[jsonrpc]` enable HTTP basic auth in websocket client ([#2434](https://github.com/cometbft/cometbft/pull/2434))

rpc/jsonrpc/client/ws_client.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"net"
@@ -35,7 +36,10 @@ type WSClient struct {
 
 	Address  string // IP:PORT or /path/to/socket
 	Endpoint string // /websocket/url/endpoint
-	Dialer   func(string, string) (net.Conn, error)
+	Username string
+	Password string
+
+	Dialer func(string, string) (net.Conn, error)
 
 	// Single user facing channel to read RPCResponses from, closed only when the
 	// client is being stopped.
@@ -96,13 +100,23 @@ func NewWS(remoteAddr, endpoint string, options ...func(*WSClient)) (*WSClient,
 		parsedURL.Scheme = protoWS
 	}
 
+	// extract username and password from URL if any
+	username := ""
+	password := ""
+	if parsedURL.User.String() != "" {
+		username = parsedURL.User.Username()
+		password, _ = parsedURL.User.Password()
+	}
+
 	dialFn, err := MakeHTTPDialer(remoteAddr)
 	if err != nil {
 		return nil, err
 	}
 
 	c := &WSClient{
 		Address:              parsedURL.GetTrimmedHostWithPath(),
+		Username:             username,
+		Password:             password,
 		Dialer:               dialFn,
 		Endpoint:             endpoint,
 		PingPongLatencyTimer: metrics.NewTimer(),
@@ -267,6 +281,12 @@ func (c *WSClient) dial() error {
 		Proxy:   http.ProxyFromEnvironment,
 	}
 	rHeader := http.Header{}
+
+	// Set basic auth header if username and password are provided
+	if c.Username != "" && c.Password != "" {
+		rHeader.Set("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(c.Username+":"+c.Password)))
+	}
+
 	conn, _, err := dialer.Dial(c.protocol+"://"+c.Address+c.Endpoint, rHeader) //nolint:bodyclose
 	if err != nil {
 		return err