style(mcp): blank line after the data: branch, as Rector asks

NewlineAfterStatementRector wants the comment that follows the
`data:` branch separated from it by an empty line.

Assisted-by: claude-code:claude-fable-5
Agent-Session: https://claude.ai/code/session_0124WZK5UoAM9oYQoSYF1Y8z
Agent-Host: 32116e
Signed-off-by: Sebastian Mendel <github@sebastianmendel.de>

Author: CybotTM

Classes/Service/Tool/Mcp/McpHttpTransport.php

@@ -382,6 +382,7 @@ private function unframeEventStream(McpServerRecord $server, string $body): stri
                 $payload = substr($line, 5);
                 $data[]  = str_starts_with($payload, ' ') ? substr($payload, 1) : $payload;
             }
+
             // `event:`, `id:`, `retry:` and `:` comments are not read.
         }