[lldb-mcp] Launch lldb on demand, if needed. (#158701) Adding support for launching lldb with `-O protocol start MCP` if a valid ~/.lldb/lldb-mcp-*.json` file is not found. --------- Co-authored-by: Jonas Devlieghere <jonas@devlieghere.com> GitOrigin-RevId: ba5ca37f40b82e287a3e0469fb0f0ea48b651aca