Bug Fixes

• transport: Fix a data race while copying headers for stats handlers in the std lib http2 server transport. (#8519)
• xdsclient:
  • Fix a data race caused while reporting load to LRS. (#8483)
  • Fix regression preventing empty node IDs when creating an LRS client. (#8483)
• server: Fix a regression preventing streams from being cancelled or timed out when blocked on flow control. (#8528)