chore: refactor tailnetAPIConnector to use dialer (#15347)

refactors `tailnetAPIConnector` to use the `Dialer` interface in `tailnet`, introduced lower in this stack of PRs. This will let us use the same Tailnet API handling code across different things that connect to the Tailnet API (CLI client, coderd, workspace proxies, and soon: Coder VPN).

chore re: #14729

codersdk/workspacesdk/workspacesdk.go

@@ -228,13 +228,13 @@ func (c *Client) DialAgent(dialCtx context.Context, agentID uuid.UUID, options *
 	q.Add("version", "2.0")
 	coordinateURL.RawQuery = q.Encode()
 
-	connector := newTailnetAPIConnector(ctx, options.Logger, agentID, coordinateURL.String(), quartz.NewReal(),
-		&websocket.DialOptions{
-			HTTPClient: c.client.HTTPClient,
-			HTTPHeader: headers,
-			// Need to disable compression to avoid a data-race.
-			CompressionMode: websocket.CompressionDisabled,
-		})
+	dialer := NewWebsocketDialer(options.Logger, coordinateURL, &websocket.DialOptions{
+		HTTPClient: c.client.HTTPClient,
+		HTTPHeader: headers,
+		// Need to disable compression to avoid a data-race.
+		CompressionMode: websocket.CompressionDisabled,
+	})
+	connector := newTailnetAPIConnector(ctx, options.Logger, agentID, dialer, quartz.NewReal())
 
 	ip := tailnet.TailscaleServicePrefix.RandomAddr()
 	var header http.Header
@@ -271,7 +271,7 @@ func (c *Client) DialAgent(dialCtx context.Context, agentID uuid.UUID, options *
 	select {
 	case <-dialCtx.Done():
 		return nil, xerrors.Errorf("timed out waiting for coordinator and derp map: %w", dialCtx.Err())
-	case err = <-connector.connected:
+	case err = <-dialer.Connected():
 		if err != nil {
 			options.Logger.Error(ctx, "failed to connect to tailnet v2+ API", slog.Error(err))
 			return nil, xerrors.Errorf("start connector: %w", err)